Mopar1973Man

DTC P1691: FUEL INJECTOR PUMP CONTROLLER CALIBRATION Monitor & Set Conditions Fuel injection pump controller calibration is monitored with ignition on engine off and with engine running and no CAN BUS errors reported. DTC may be set when PCM fuel injector pump controller and ECM RPM are mismatched or fuel commanded does not equal amount fueled. Possible Causes Fuel Injection Pump Failure DTC Returns Testing 1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If DTC P1691 does not exist, go to next step. If DTC P1691 exists, replace fuel injection pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 2. Using scan tool, clear DTCs. Start engine and allow engine to idle for one minute. Using scan tool, check for DTCs. If DTC P1691 does not exist, test is complete. If DTC P1691 exists, replace fuel injection pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.

DTC P1690: FUEL INJECTION PUMP CKP SENSOR DOES NOT AGREE WITH ECM CKP SENSOR Monitor & Set Conditions Fuel Injection Pump Crankshaft Position (CKP) circuit is monitored when ignition is on and engine is running. DTC may be stored when no signal exists within specified window parameters with no Camshaft Position (CMP) sensor or CKP DTCs present. Possible Causes AC Noise Across Fuel Transfer Pump Other DTCs Present Wiring & Connectors Fuel Injection Pump Static Timing Fuel Sync Signal Circuit Open Fuel Sync Signal Circuit Short To Ground ECM Testing 1. Measure AC noise to ECM by connecting DVOM between ground and terminals No. 48 and 50 (Red/White wires) at ECM harness connector. If AC voltage is 25 mV rms or less, go to next step. If AC voltage is greater than 25 mV rms, replace fuel transfer pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 2. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If no additional DTCs exist, go to next step. If any additional DTCs exist, repair other DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . 3. Using scan tool, check Good Trip Counter for DTC P1690. If Good Trip Counter for DTC P1690 is displayed and equal to zero, go to next step. If Good Trip Counter for DTC P1690 is displayed and not equal to zero, go to step 5 . 4. Turn ignition off. Disconnect FPCM harness connector. FPCM harness connector is located on end of fuel injection pump. Check for poor connection/terminal contact at FPCM harness connector. Repair as necessary. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Check for poor connection/terminal contact at ECM harness connector. Repair as necessary. Using DVOM, measure resistance of Dark Green wire between terminal No. 8 on FPCM harness connector and terminal No. 18 on ECM harness connector. If resistance is less than 5 ohms, go to step 7 . If resistance is 5 ohms or greater, repair open in Dark Green wire between FPCM and ECM. 5. Turn ignition off. At this time, conditions required for DTC to be stored are not present. Inspect wiring and connectors between FPCM and ECM. FPCM is located on top of fuel injection pump. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary. 6. Check fuel injection pump timing. See CHECKING FUEL INJECTION PUMP TIMING under FUEL INJECTION PUMP TIMING in ON-VEHICLE ADJUSTMENTS - RAM PICKUP - DIESEL article. If fuel injection pump timing is okay, go to next step. If fuel injection pump timing requires adjustment, adjust fuel injection pump timing as necessary. 7. Ensure ignition is off. Disconnect FPCM harness connector. FPCM harness connector is located on end of fuel injection pump. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Using DVOM, measure resistance between ground and terminal No. 8 (Dark Green wire) on FPCM harness connector. If resistance is 5 ohms or greater, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If resistance is less than 5 ohms, repair short to ground in Dark Green wire between FPCM and ECM.

DTC P1689: NO COMMUNICATION BETWEEN ECM & INJECTION PUMP MODULE (OBDII) Monitor & Set Conditions Communication between Engine Control Module (ECM) and fuel injection pump module is monitored when ignition is on. Injection pump module is referred to as Fuel Pump Control Module (FPCM) in test procedures. DTC may be stored if the time between CAN messages is more than 3 seconds or FPCM does not receive CAN message. Possible Causes Wiring & Connectors Fuel Injection Pump Relay Output Circuit Open Ground Circuit Open Or High Resistance Datalink (+) Circuit Open Datalink (+) Circuit Shorted To Ground Datalink (-) Open Datalink (-) Shorted To Ground ECM Testing 1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1689 is displayed and not equal to zero, go to next step. If Good Trip Counter for DTC P1689 is displayed and equal to zero, go to step 3 . 2. Turn ignition off. At this time, conditions required for DTC to be stored are not present. Inspect wiring and connectors between FPCM and ECM. FPCM located on top of fuel injection pump. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary. 3. Ensure ignition is off. Disconnect FPCM harness connector. FPCM harness connector is located on end of fuel injection pump. Check for poor connection/terminal contact at FPCM harness connector. Repair as necessary. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 7 (Red/Light Green wire) on FPCM harness connector. If voltage is 8 volts or greater, go to next step. If voltage is less than 8 volts, perform DTC P0215: FUEL INJECTION PUMP CONTROL CIRCUIT test. 4. Turn ignition off. Ensure FPCM connector is still disconnected. Disconnect ECM harness connector. Check for poor connection/terminal contact at ECM harness connector. Repair as necessary. Connect a test light between battery voltage and terminal No. 6 (Black/Tan wire) on FPCM connector. This is the ground circuit for FPCM. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance on Black/Tan wire between FPCM and ground connection. Ground connection is located at ground connection for negative battery terminal. 5. Ensure ignition is off and FPCM harness connector and ECM harness connector are still disconnected. Using DVOM, measure resistance of White wire between terminal No. 2 on FPCM harness connector and terminal No. 13 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open or high resistance in White wire between FPCM and ECM. 6. Ensure ignition is off and FPCM harness connector and ECM harness connector are still disconnected. Using DVOM, measure resistance between ground and terminal No. 2 (White wire) on FPCM connector. If resistance is 5 ohms or greater, go to next step. If resistance is less than 5 ohms, repair short to ground in White wire between FPCM and ECM. 7. Ensure ignition is off and FPCM harness connector and ECM harness connector are still disconnected. Using DVOM, measure resistance of Black wire between terminal No. 1 on FPCM harness connector and terminal No. 23 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open or high resistance in Black wire between FPCM and ECM. 8. Ensure ignition is off and FPCM harness connector and ECM harness connector are still disconnected. Using DVOM, measure resistance between ground and terminal No. 1 (Black wire) on FPCM harness connector. If resistance is 5 ohms or greater, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If resistance is less than 5 ohms, repair short to ground in Black wire between FPCM and ECM.

DTC P1688: INTERNAL FUEL INJECTION PUMP FAILURE Monitor & Set Conditions Fuel Pump Control Module (FPCM) is monitored with ignition on engine off, and with engine running. DTC may set if FPCM, PCM memory, programming or hardware error is detected. Possible Causes Good Trip Counter Equals Zero Fuel Pump Control Module (FPCM) Testing 1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1688 is displayed and not equal to zero, go to next step. If Good Trip Counter for DTC P1688 is displayed and equal to zero, replace FPCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 2. Ensure ignition is on with engine off. Using scan tool, check for DTCs and record FREEZE FRAME data. Try to duplicate conditions recorded in FREEZE FRAME data. Using scan tool, check for DTCs. If DTC P1688 returns, replace fuel injection pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If DTC P1688 does not return, test is complete.

DTC P1687: NO CLUSTER BUS MESSAGE 1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is displayed and equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is not displayed and equal to zero, go to step 5 . 2. Turn ignition off. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Note location of connectors C1 and C2 on instrument cluster. See Fig. 61 . Disconnect connector C1 from rear of instrument cluster. It may be necessary to remove instrument cluster for access to connectors on rear of instrument cluster. 3. Using ohmmeter, check resistance between terminal No. 10 (Violet/Brown wire) on connector C1 for instrument cluster and terminal No. 30 (Violet/Brown wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Violet/Brown wire between instrument cluster and PCM. Perform TEST VER-2A . 4. Using ohmmeter, check resistance between terminal No. 9 (White/Black wire) on connector C1 for instrument cluster and terminal No. 28 (White/Black wire) on PCM connector C3. If resistance is less than 5 ohms, replace instrument cluster. Perform TEST VER-2A . If resistance is 5 ohms or more, repair open on White/Black wire between instrument cluster and PCM. Perform TEST VER-2A . 5. Turn ignition off. It is assumed that an intermittent problem exists with wiring or connectors. Inspect instrument cluster and PCM connectors for miswired, corroded, pushed out or damaged terminals. Inspect instrument cluster and PCM wiring for chafed, pierced or partially broken wires. If terminals are not miswired, corroded, pushed out or damaged and wiring is okay, check for Technical Service Bulletins (TSBs) that may apply. If no problems are found and no TSBs exist, test is complete. If terminals are miswired, corroded, pushed out or damaged, or wiring is damaged, repair as necessary. Perform TEST VER-2A .

DTC P1683: SPEED CONTROL POWER RELAY OR SPEED CONTROL 12V DRIVER CIRCUIT 1. Ensure ignition is off. Disconnect speed control servo connector. Speed control servo is located below driver's side battery tray. See Fig. 59 . 2. Turn ignition on with engine off. Using scan tool, actuate speed control servo. Using 12-volt test light, check for voltage at terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. DO NOT depress brake pedal when checking voltage. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, go to step 8 . 3. Turn ignition off. Ensure speed control servo connector is still disconnected. Using ohmmeter, check resistance between ground and terminal No. 4 (Black wire) on speed control servo connector. DO NOT depress brake pedal when checking resistance. If resistance less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Black wire between speed control servo and ground connection. Ground connection is located on driver's side fender panel, just below speed control servo. Perform TEST VER-4A . 4. Ensure ignition is off and speed control servo connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between terminal No. 1 (Tan/Red wire) on speed control servo connector and terminal No. 4 (Tan/Red wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance 5 ohms or more, repair open on Tan/Red wire between speed control servo and PCM. Perform TEST VER-4A . 5. Ensure speed control servo connector and PCM connectors are still disconnected. Using ohmmeter, check resistance between ground and terminal No. 1 (Tan/Red wire) on speed control servo connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Tan/Red wire between speed control servo and PCM. Perform TEST VER-4A . 6. Ensure speed control servo connector and PCM connectors are still disconnected. Using ohmmeter, check No. 5 (Light Green/Red wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance 5 ohms or more, repair open on Light Green/Red wire between speed control servo and PCM. Perform TEST VER-4A . 7. Ensure speed control servo connector and PCM connectors are still disconnected. Using ohmmeter, check resistance between ground and terminal No. 2 (Light Green/Red wire) on speed control servo connector. If resistance is 5 ohms or more, replace speed control servo. Perform TEST VER-4A . If resistance is less than 5 ohms, repair short to ground on Light Green/Red wire between speed control servo and PCM. Perform TEST VER-4A . 8. Turn ignition off. Disconnect brake switch connector. Start engine and allow engine to idle. Place speed control switch in ON position. Shut engine off. Turn ignition on with engine off. Using scan tool, actuate speed control servo. Using 12-volt test light, check for voltage at terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. DO NOT depress brake pedal when checking for voltage. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, go to step 12 . 9. Brake switch adjustment should be checked. Reinstall brake switch connector. To check brake switch adjustment, depress brake pedal. Ensure brakelights come on. Release brake pedal. Ensure brakelights go off. If brake switch is properly adjusted and brakelight operation is as specified, go to next step. If and brakelight operation is not as specified, replace brake switch, as brake switch is nonadjustable and can only be adjusted when NEW brake switch is installed. Perform TEST VER-4A . 10. Ensure ignition is off and speed control servo connector is still disconnected. Using ohmmeter, check resistance between ground and terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. If resistance 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Blue/Red wire between speed control servo and brake switch. Perform TEST VER-4A . 11. Disconnect brake switch connector. Using ohmmeter, check resistance between terminal No. 4 (Dark Blue/Red wire) on brake switch connector and terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. If resistance is less than 5 ohms, replace brake switch. Perform TEST VER-4A . If resistance 5 ohms or more, repair open on Dark Blue/Red wire between brake switch and speed control servo. Perform TEST VER-4A . 12. Ensure ignition is off and speed control servo connector is still disconnected. Using ohmmeter, check resistance between ground and terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. If resistance 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Blue/Red wire between speed control servo and brake switch. Perform TEST VER-4A . 13. Ensure ignition is off and speed control servo connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between terminal No. 3 (Yellow/Red wire) on brake switch connector and terminal No. 11 (Yellow/Red wire) on PCM connector C3. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-4A . If resistance 5 ohms or more, repair open on Yellow/Red wire between brake switch and PCM. Perform TEST VER-4A .

DTC P1682: CHARGING SYSTEM VOLTAGE TOO LOW 1. Ensure battery is fully charged and generator drive belt is in good condition and properly adjusted before proceeding. Start engine and allow engine to idle. Using scan tool, read target charging voltage. If target charging voltage is more than 15.1 volts, go to next step. If target charging voltage is 15.1 volts or less, go to step 4 . 2. Ensure engine is idling and at normal operating temperature. Using scan tool, read temperature of battery temperature sensor. Using thermometer, measure underhood temperature near battery tray. If underhood temperature is not within 10 degrees of temperature of battery temperature sensor, go to next step. If underhood temperature is within 10 degrees of temperature of battery temperature sensor, go to step 4 . 3. Shut engine off. Ensure ignition is off. Disconnect battery temperature sensor connector. Battery temperature sensor is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. Connect jumper wire between electrical terminals on battery temperature sensor connector. Turn ignition on with engine off. Using scan tool, read battery temperature sensor voltage. Battery temperature sensor voltage may also abe referred to as BTS voltage. If battery temperature sensor voltage is more than zero volts, replace PCM. Perform TEST VER-3A . PCM is located at passenger's side rear corner of engine compartment. If battery temperature sensor voltage is zero volts, replace battery temperature sensor. Perform TEST VER-3A . 4. Ensure engine is idling and at normal operating temperature. Turn on all accessories. Adjust engine speed to 1600 RPM. Using scan tool, read target charging voltage and charging voltage. Compare the 2 readings. If difference between the 2 readings is more than one volt, go to next step. If difference between the 2 readings is one volt or less, go to step 12 . 5. Shut engine off. Ensure ignition is off. Connect voltmeter between positive terminal on the battery and positive battery terminal on rear of the generator. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is .4 volt or less, go to next step. If voltage is more than .4 volt, repair high resistance between positive battery terminal and positive battery terminal on rear of the generator. Perform TEST VER-3A . 6. Shut engine off. Ensure ignition is off. Connect voltmeter between case of generator and negative battery terminal. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is .1 volt or less, go to next step. If voltage is more than .1 volt, repair generator for high resistance between generator case and negative battery terminal. Perform TEST VER-3A . 7. Shut engine off. Turn ignition on with engine off. Using scan tool, actuate generator field driver. Using voltmeter, check voltage at each terminal in 2-wire connector at rear of generator. If voltage is less than 3 volts at either terminal, go to next step. If voltage is 3 volts or more at both terminals, charging system is operating properly at this time. 8. Turn ignition off. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Disconnect round 2-wire connector at rear of the generator. Using ohmmeter, check resistance between ground and terminal No. 10 (Dark Green wire) on PCM connector C2. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Green wire between PCM and round 2-wire connector for the generator and replace PCM. Perform TEST VER-3A . 9. Ensure PCM connectors and round 2-wire connector at rear of generator are still disconnected. Using ohmmeter, check resistance between terminal No. 1 (Dark Green wire) on round 2-wire connector for the generator and terminal No. 10 (Dark Green wire) on PCM connector C2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Green wire between PCM and round 2-wire connector for the generator. Perform TEST VER-3A . 10. Ensure PCM connectors and round 2-wire connector at rear of generator are still disconnected. Using ohmmeter, check resistance between ground and terminal No. 25 (Dark Blue wire) on PCM connector C3. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Blue wire between PCM and round 2-wire connector for the generator. Perform TEST VER-3A . 11. Ensure PCM connectors and round 2-wire connector at rear of generator are still disconnected. Using ohmmeter, check resistance between terminal No. 2 (Dark Blue wire) on round 2-wire connector for the generator and terminal No. 25 (Dark Blue wire) on PCM connector C3. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-3A . If resistance is 5 ohms or more, repair open on Dark Blue wire between PCM and round 2-wire connector for the generator. Perform TEST VER-3A . 12. Shut engine off. Ensure ignition is off. Connect voltmeter between positive battery terminal on rear of generator and positive battery terminal. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is .4 volt or less, go to next step. If voltage is more than .4 volt, repair high resistance on Black wire and Red wire between generator and the battery. Perform TEST VER-3A . 13. Turn ignition off. Connect voltmeter between generator case and negative battery terminal. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is .1 volt or less, test is complete. If voltage is more than .1 volt, repair generator ground for high resistance between generator case and negative battery terminal. Perform TEST VER-3A .

DTC P1597: SPEED CONTROL SWITCH ALWAYS LOW 1. Start engine and allow engine to idle. Using scan tool in SENSORS mode, read speed control switch voltage. Speed control switch voltage may also be referred to as S/C switch voltage. If speed control switch voltage is less than one volt, go to next step. If speed control switch voltage is one volt or more, conditions required for DTC to be set are not present at this time. Test is complete. 2. Shut engine off. Ensure ignition is off. Disconnect speed control on/off switch 2-pin connector at rear of speed control on/off switch assembly on steeering wheel. Start engine and allow engine to idle. Using scan tool in SENSORS mode, read speed control switch voltage. If speed control switch voltage does not change to 5 volts, go to next step. If speed control switch voltage changes to 5 volts, replace speed control on/off switch. Perform TEST VER-4A . 3. Shut engine off. Ensure ignition is off. Disconnect speed control resume/accel switch 2-pin connector at rear of speed control resume/accel switch assembly on steering wheel. Start engine and allow engine to idle. Using scan tool in SENSORS mode, read speed control switch voltage. If speed control switch voltage does not change to 5 volts, go to next step. If speed control switch voltage changes to 5 volts, replace speed control resume/accel switch. Perform TEST VER-4A . 4. Shut engine off. Ensure ignition is off and connectors are still disconnected at speed control on/off and resume/accel switches. Using ohmmeter, check resistance between terminals No. 1 (White wire) and No. 2 (Dark Green/Red wires) on speed control on/off switch connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair White and Dark Green/Red wires to speed control on/off and resume/accel switches at they are shorted together. These wires go from speed control on/off and resume/accel switches, through clockspring and to PCM. PCM is located at passenger's side rear corner of engine compartment. Perform TEST VER-4A . 5. Ensure connectors are still disconnected at speed control on/off and resume/accel switches. Disconnect clockspring connector C1. See Fig. 60 . Using ohmmeter, check resistance between ground and terminal No. 1 (Red/Light Green wire) on clockspring connector C1. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 7 . 6. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between ground and terminal 1 (Red/Light Green wire) on clockspring connector C1. If resistance is still less than 5 ohms, repair short to ground on Red/Light Green wire between PCM and clockspring. Perform TEST VER-4A . If resistance now 5 ohms or more, replace PCM. Perform TEST VER-4A . 7. Ensure connectors are still disconnected at speed control on/off and resume/accel switches. Disconnect clockspring connector C2. See Fig. 60 . Using ohmmeter, check resistance between ground and terminal "A" (Dark Green/Red wire) on clockspring connector C2. If resistance is 5 ohms or more, replace clockspring. Perform TEST VER-4A . If resistance is less than 5 ohms, repair short to ground on Dark Green/Red wire between clockspring and speed control on/off and resume/accel switches. Perform TEST VER-4A .

DTC P1596: SPEED CONTROL SWITCH ALWAYS HIGH 1. Start engine and allow engine to idle. Using scan tool in INPUTS/OUTPUTS mode, read speed control inputs. Monitor display on scan tool while turning speed control on/off switch on the steering wheel to ON and OFF positions several times with the switch returned to the ON position. If scan tool displays speed control on/off switch turns OFF and ON, go to next step. If scan tool does not display speed control on/off switch turns OFF and ON, go to step 3 . 2. At this time, conditions required for DTC to be stored are not present. Ensure engine is idling. Using scan tool, monitor speed control on/off switch voltage while wiggling wiring harness and connectors between speed control on/off switch and PCM. PCM is located at passenger's side rear corner of engine compartment. If voltage is not more than 4.9 volts at any time while wiggling wiring harness and connectors, test is complete. If voltage is more than 4.9 volts at any time while wiggling wiring harness and connectors, repair wiring or connector as necessary that caused the voltage to fluctuate. Perform TEST VER-4A . 3. Shut engine off. Ensure ignition is off. Disconnect speed control on/off switch 2-pin connector at rear of speed control on/off switch assembly. DO NOT disconnect any other connectors except the 2-pin connector. Using ohmmeter, check resistance between ground and terminal No. 1 (White wire) on speed control on/off switch 2-pin connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open ground circuit on White wire. The White wire goes from speed control on/off switch, through clockspring and then changes to Black/Light Blue wire at clockspring and goes to terminal No. 4 on PCM connector C1. Clockspring is located on steering column, just below steering wheel. See Fig. 60 . PCM is located at passenger's side rear corner of engine compartment. Perform TEST VER-4A . 4. Ensure speed control on/off switch 2-pin connector at rear of speed control on/off switch assembly is still disconnected. Start engine and allow engine to idle. Using voltmeter, check voltage at terminal No. 2 (Dark Green/Red wire) on speed control on/off switch 2-pin connector. If voltage is less than 6 volts, go to next step. If voltage is more than 6 volts, repair short to voltage on Dark Green/Red wire. The Dark Green/Red wire goes from speed control on/off switch, through clockspring and then changes to Red/Light Green wire at clockspring and goes to terminal No. 32 on PCM connector C3. Clockspring is located on steering column, just below steering wheel. See Fig. 60 . PCM is located at passenger's side rear corner of engine compartment. Perform TEST VER-4A . 5. Shut engine off. Ensure ignition is off and speed control on/off switch 2-pin connector at rear of speed control on/off switch assembly is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between terminal No. 32 (Red/Light Green wire) on PCM connector C3 and terminal No. 2 (Dark Green/Red wire) on speed control on/off switch 2-pin connector. The Dark Green/Red wire goes from speed control on/off switch, through clockspring and then changes to Red/Light Green wire at clockspring and goes to terminal No. 32 on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 7 . 6. Using ohmmeter, check resistance between electrical terminals on speed control on/off switch. If resistance is 20,300-20,700 ohms, replace PCM. Perform TEST VER-4A . If resistance is not 20,300-20,700 ohms, replace speed control on/off switch. Perform TEST VER-4A . 7. Ensure ignition off and PCM connectors are still disconnected. Disconnect clockspring connector C1. See Fig. 60 . Using ohmmeter, check resistance between terminal No. 1 (Red/Light Green wire) on clockspring connector C1 and terminal No. 32 (Red/Light Green wire) on PCM connector C3. If resistance is less than 5 ohms, replace clockspring. Perform TEST VER-4A . If resistance is 5 ohms or more, repair open on Red/Light Green wire between clockspring and PCM. Perform TEST VER-4A .

DTC P1595: SPEED CONTROL SOLENOID CIRCUITS 1. Turn ignition on with engine off. Using scan tool, actuate speed control vent solenoid and listen for operating sound (click) at speed control servo. Speed control servo is located below driver's side battery tray. See Fig. 59 . If operating sound is heard at speed control servo, go to next step. If operating sound is not heard at speed control servo, go to step 6 . 2. Ensure ignition is on and speed control vent solenoid is still actuated. Wiggle wiring harness and connectors between speed control servo, brake switch and PCM while checking for interruption of speed control vent solenoid actuation. Brake switch is located near top of brake pedal. PCM is located at passenger's side rear corner of engine compartment. If speed control vent solenoid actuation was not interrupted while wiggling wiring harness and connectors, stop actuation of speed control vent solenoid. Go to next step. If speed control vent solenoid actuation was interrupted while wiggling wiring harness and connectors, stop actuation of speed control vent solenoid. Repair wiring or connectors as necessary. Perform TEST VER-4A . 3. Ensure ignition is on with engine off. Using scan tool, actuate speed control vacuum solenoid and listen for operating sound (click) at speed control servo. If operating sound is heard at speed control servo, go to next step. If operating sound is not heard at speed control servo, go to step 6 . 4. Ensure ignition is on and speed control vacuum solenoid is still actuated. Wiggle wiring harness and connectors between speed control servo, brake switch and PCM while checking for interruption of speed control vacuum solenoid actuation. If speed control vacuum solenoid actuation was not interrupted while wiggling wiring harness and connectors, stop actuation of speed control vacuum solenoid. Go to next step. If speed control vacuum solenoid actuation was interrupted while wiggling wiring harness and connectors, stop actuation of speed control vacuum solenoid. Repair wiring or connectors as necessary. Perform TEST VER-4A . 5. Turn ignition off. Inspect wiring harness and connectors between speed control servo, brake switch and PCM. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-4A . 6. Turn ignition off. Disconnect speed control servo connector. Turn ignition on with engine off. Using scan tool, actuate speed control vent or speed control vacuum solenoid. Using 12-volt test light, check for voltage at terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. DO NOT depress brake pedal when checking voltage. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, go to step 12 . 7. Turn ignition off. Ensure speed control servo connector is still disconnected. Using ohmmeter, check resistance between ground and terminal No. 4 (Black wire) on speed control servo connector. If resistance less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Black wire between speed control servo and ground connection. Ground connection is located on driver's side fender panel. Perform TEST VER-4A . 8. Ensure ignition is off and speed control servo connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between ground and terminal No. 1 (Tan/Red wire) on speed control servo connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Tan/Red wire between speed control servo and PCM. Perform TEST VER-4A . 9. Ensure speed control servo connector and PCM connectors are still disconnected. Using ohmmeter, check resistance between ground and terminal No. 2 (Light Green/Red wire) on speed control servo connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Light Green/Red wire between speed control servo and PCM. Perform TEST VER-4A . 10. Ensure speed control servo connector and PCM connectors are still disconnected. Using ohmmeter, check resistance between terminal No. 1 (Tan/Red wire) on speed control servo connector and terminal No. 4 (Tan/Red wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance 5 ohms or more, repair open on Tan/Red wire between speed control servo and PCM. Perform TEST VER- 4A . 11. Ensure speed control servo connector and PCM connectors are still disconnected. Using ohmmeter, check resistance between terminal No. 2 (Light Green/Red wire) on speed control servo connector and terminal No. 5 (Light Green/Red wire) on PCM connector C3. If resistance is less than 5 ohms, replace speed control servo. Perform TEST VER-4A . If resistance 5 ohms or more, repair open on Light Green/Red wire between speed control servo and PCM. Perform TEST VER-4A . 12. Turn ignition off. Ensure speed control servo connector is still disconnected. Using ohmmeter, check resistance between ground and terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Blue/Red wire between speed control servo and brake switch. Brake switch is located near top of brake pedal. Perform TEST VER-4A . 13. Disconnect brake switch connector. Turn ignition on with engine off. Using scan tool, actuate speed control vent solenoid or speed control vacuum solenoid. Using 12-volt test light, check for voltage at terminal No. 3 (Yellow/Red wire) on brake switch connector. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, go to step 16 . 14. Brake switch adjustment should be checked. Reinstall brake switch connector. To check brake switch adjustment, depress brake pedal. Ensure brakelights come on. Release brake pedal. Ensure brakelights go off. If brake switch is properly adjusted and brakelight operation is as specified, go to next step. If and brakelight operation is not as specified, replace brake switch, as brake switch is nonadjustable and can only be adjusted when NEW brake switch is installed. Perform TEST VER-4A . 15. Disconnect brake switch connector. Ensure speed control servo connector is still disconnected. Using ohmmeter, check resistance between terminal No. 4 (Dark Blue/Red wire) on brake switch connector and terminal No. 3 (Dark Blue/Red wire) on speed control servo connector. If resistance is less than 5 ohms, replace brake switch. Perform TEST VER-4A . If resistance is 5 ohms or more, repair open on Dark Blue/Red wire between brake switch and speed control servo. Perform TEST VER-4A . 16. Ensure ignition is off and brake switch connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between terminal No. 3 (Yellow/Red wire) on brake switch connector and terminal No. 11 (Yellow/Red wire) on PCM connector C3. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-4A . If resistance is 5 ohms or more, repair open on Yellow/Red wire between brake switch and PCM. Perform TEST VER-4A

DTC P1594: CHARGING SYSTEM VOLTAGE TOO HIGH 1. Turn ignition on with engine off. Using scan tool, actuate generator field driver. Using 12-volt test light, check for voltage at terminal No. 1 (Dark Green wire) on 2-wire connector at rear of generator. If test light blinks on and off, go to next step. If test light does not blink on and off, go to step 5 . 2. Start engine and allow engine to idle. Using scan tool, read target charging voltage. If target charging voltage is more than zero volts, go to next step. If target charging voltage is zero volts, go to step 4 . 3. With engine running, manually set engine speed to 1600 RPM. Using scan tool, read target charging voltage and battery voltage. Compare the 2 readings for 5 minutes. If difference between the 2 readings is more than one volt, replace PCM. Perform TEST VER-3A . PCM is located at passenger's side rear corner of engine compartment. If voltage difference is not more than one volt, allow engine to return to idle. Shut engine off. Turn ignition on with engine off. Using scan tool, check for DTCs. Record DTCs and FREEZE FRAME data, then clear DTCs. Perform TEST VER-3A . 4. Shut engine off. Using scan tool, read temperature of battery temperature sensor. Using thermometer, measure underhood temperature near battery tray. If underhood temperature is within 10 degrees of temperature of battery temperature sensor, replace PCM. Perform TEST VER-3A . PCM is located at passenger's side rear corner of engine compartment. If underhood temperature is not within 10 degrees of temperature of battery temperature sensor, replace battery temperature sensor. Perform TEST VER-3A . 5. Ensure ignition is off. Disconnect 2-wire connector at rear of generator. Disconnect round 2-wire connector at rear of the generator. Using ohmmeter, check resistance between ground and generator field driver terminal in the generator. This is the terminal on rear of generator that Dark Green wire in the round 2-wire connector fits on. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, short exists in the generator. Repair or replace generator as necessary. Perform TEST VER-3A . 6. Ensure ignition is off and 2-wire connector at rear of generator is still disconnected . Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Disconnect battery. Using ohmmeter, check resistance between ground and terminal No. 10 (Dark Green wire) on PCM connector C2. If resistance is 5 ohms or more, replace PCM. Perform TEST VER-3A . If resistance is less than 5 ohms, repair short to ground on Dark Green wire between generator and PCM. Perform TEST VER-3A .

DTC P1493: AMBIENT/BATTERY TEMPERATURE SENSOR VOLTS TOO LOW 1. Turn ignition on with engine off. Using scan tool, read battery temperature sensor voltage. Battery temperature sensor voltage may also be referred to as BTS voltage. If battery temperature sensor voltage is less than .5 volt, go to next step. If battery temperature sensor voltage is .5 volt or more, go to step 5 . 2. Turn ignition off. Disconnect battery temperature sensor connector. Battery temperature sensor is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. Turn ignition on with engine off. Using scan tool, read battery temperature sensor voltage. If battery temperature sensor voltage is 4 volts or less, go to next step. If battery temperature sensor voltage is more than 4 volt, replace battery temperature sensor. Perform TEST VER-5A . 3. Turn ignition off. Ensure battery temperature sensor connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between ground and terminal No. 2 (Pink/Yellow wire) on battery temperature sensor connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Pink/Yellow wire between battery temperature sensor and PCM. Perform TEST VER-5A . 4. Ensure battery temperature sensor connector and PCM connectors are still disconnected. Using ohmmeter, check resistance between terminals No. 1 (Black/Light Blue wire) and No. 2 (Pink/Yellow wire) on battery temperature sensor connector. If resistance is 5 ohms or more, replace PCM. Perform TEST VER-5A . If resistance is less than 5 ohms, repair Black/Light Blue wire and Pink/Yellow wire between PCM and battery temperature sensor as they are shorted together. Perform TEST VER-5A . 5. Ensure ignition is on with engine off. While using scan tool to monitor battery temperature sensor voltage, wiggle wiring harness and connectors between battery temperature sensor and PCM. Battery temperature sensor is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. PCM is located at passenger's side rear corner of engine compartment. If battery temperature sensor voltage does not change while wiggling wiring harness and connectors, go to next step. If battery temperature sensor voltage changes while wiggling wiring harness and connectors, repair wiring or connector as necessary. Perform TEST VER-5A . 6. Turn ignition off. Inspect wiring harness and connectors between battery temperature sensor and PCM. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-5A . 7. Ensure ignition is on with engine off. At this time, DTC is intermittent. Using scan tool, go to FREEZE FRAME data and ensure CAUSED BY DTC hex code is the same as DTC on DTC screen. If DTCs displayed are not the same, repair DTC displayed with FREEZE FRAME data. If DTCs displayed are the same, try to duplicate conditions recorded in FREEZE FRAME data. Inspect battery temperature sensor connector and PCM connectors for corroded, pushed out or damaged terminals. Inspect wiring harness and connectors between battery temperature sensor and PCM for chafed, pierced or partially broken wires. If terminals are not corroded, pushed out or damaged and wiring is okay, check for Technical Service Bulletins (TSBs) that may apply. If terminals are corroded, pushed out or damaged, or wiring is damaged, repair as necessary. Perform TEST VER-5A

DTC P1492: AMBIENT/BATT TEMP SEN VOLTS TOO HIGH 1. Turn ignition on with engine off. Using scan tool, read battery temperature sensor voltage. Battery temperature sensor voltage may also be referred to as BTS voltage. If battery temperature sensor voltage is more than 4.5 volts, go to next step. If battery temperature sensor voltage is 4.5 volts or less, go to step 6 . 2. Turn ignition off. Disconnect battery temperature sensor connector. Battery temperature sensor is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. Connect jumper wire between engine ground and terminal No. 2 (Pink/Yellow wire) on battery temperature sensor connector. Turn ignition on with engine off. Using scan tool, read battery temperature sensor voltage. If battery temperature sensor voltage is one volt or more, go to next step. If battery temperature sensor voltage is less than one volt, repair open on Black/Light Blue wire between battery temperature sensor, joint connector No. 1 and PCM. This is the ground circuit for battery temperature sensor. Joint connector No. 1 is located in power distribution center at driver's side front corner of engine compartment. See Fig. 54 . PCM is located at passenger's side rear corner of engine compartment. Perform TEST VER-5A . 3. Turn ignition off. Disconnect jumper wire from engine ground and reconnect to terminal No. 1 (Black/Light Blue wire) on battery temperature sensor connector. Ensure other end of jumper wire is still connected to terminal No. 2 (Pink/Yellow wire) on battery temperature sensor connector. Turn ignition on with engine off. Using scan tool, read battery temperature sensor voltage. If battery temperature sensor voltage is one volt or more, go to next step. If battery temperature sensor voltage is less than one volt, replace battery temperature sensor sensor. Perform TEST VER-5A . 4. Ensure ignition is on with engine off. Using voltmeter, check voltage at terminal No. 2 (Pink/Yellow wire) on battery temperature sensor connector. If voltage is 6 volts or less, go to next step. If voltage is more than 6 volts, repair short to voltage on Pink/Yellow wire between battery temperature sensor and PCM. PCM is located at passenger's side rear corner of engine compartment. Perform TEST VER-5A . 5. Turn ignition off. Ensure battery temperature sensor connector is still disconnected. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between terminal No. 2 (Pink/Yellow wire) on battery temperature sensor connector and terminal No. 15 (Pink/Yellow wire) on PCM connector C3. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-5A . If resistance is 5 ohms or more, repair open on Pink/Yellow wire between battery temperature sensor and PCM. Perform TEST VER-5A . 6. Ensure ignition is on with engine off. While using scan tool to monitor battery temperature sensor voltage, wiggle wiring harness and connectors between battery temperature sensor and PCM. Battery temperature sensor is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. PCM is located at passenger's side rear corner of engine compartment. If battery temperature sensor voltage does not change while wiggling wiring harness and connectors, go to next step. If battery temperature sensor voltage changes while wiggling wiring harness and connectors, repair wiring or connector as necessary. Perform TEST VER-5A . 7. Turn ignition off. Inspect wiring harness and connectors between battery temperature sensor and PCM. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-5A . 8. Turn ignition on with engine off. At this time, DTC is intermittent. Using scan tool, go to FREEZE FRAME data and ensure CAUSED BY DTC hex code is the same as DTC on DTC screen. If DTCs displayed are not the same, repair DTC displayed with FREEZE FRAME data. If DTCs displayed are the same, try to duplicate conditions recorded in FREEZE FRAME data. Inspect battery temperature sensor connector and PCM connectors for corroded, pushed out or damaged terminals. Inspect wiring harness and connectors between battery temperature sensor and PCM for chafed, pierced or partially broken wires. If terminals are not corroded, pushed out or damaged and wiring is okay, check for Technical Service Bulletins (TSBs) that may apply. If terminals are corroded, pushed out or damaged, or wiring is damaged, repair as necessary. Perform TEST VER-5A .

DTC P1488: AUXILIARY 5 VOLT OUTPUT TOO LOW Monitor & Set Conditions Auxiliary 5-volt output circuit is monitored with ignition on engine off, and with engine running. DTC may set if voltage on 5-volt sensor supply circuit is less than 4.3 volts for 5 seconds. Possible Causes Manifold Absolute Pressure (MAP) Sensor Camshaft Position (CMP) Sensor Engine Oil Pressure Sensor Water In Fuel Sensor 5-volt Supply Circuit Shorted To Ground 5-volt Supply Circuit Open Broken, Bent Or Pushed Out Terminals ECM Testing 1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1488 is displayed and equal to zero, go to next step. If Good Trip Counter for DTC P1488 is displayed and not equal to zero, go to step 8 . 2. Turn ignition off. Disconnect MAP sensor harness connector. MAP sensor is located on driver's side rear corner of cylinder head. Check for poor connection/terminal contact at MAP sensor harness connector. Repair as necessary. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 1 (Orange wire) on MAP sensor harness connector. If voltage is 4.5 volts or less, go to next step. If voltage is greater than 4.5 volts, replace MAP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 3. Turn ignition off. Ensure MAP sensor harness connector is still disconnected. Disconnect CMP sensor harness connector. CMP sensor is located on rear of timing gear cover, directly below bottom of fuel injection pump. Check for poor connection/terminal contact at CMP sensor harness connector. Repair as necessary. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 1 (Orange wire) on MAP sensor harness connector. If voltage is 4.5 volts or less, go to next step. If voltage is greater than 4.5 volts, replace CMP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 4. Turn ignition off. Ensure MAP sensor harness connector and CMP sensor harness connector are still disconnected. Disconnect engine oil pressure sensor harness connector. Engine oil pressure sensor is located on driver's side of cylinder block, just behind Engine Control Module (ECM) and contains 3-pin connector. Engine oil pressure sensor may also be referred to as oil pressure sensor. Check for poor connection/terminal contact at oil pressure sensor harness connector. Repair as necessary. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 1 (Orange wire) on MAP sensor harness connector. If voltage is 4.5 volts or less, go to next step. If voltage is greater than 4.5 volts, replace engine oil pressure sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 5. Turn ignition off. Ensure MAP sensor harness connector, CMP harness connector and oil pressure sensor harness connector are still disconnected. Disconnect Water In Fuel (WIF) sensor harness connector. WIF sensor is located at bottom of fuel filter/water separator on driver's side of engine, just behind fuel injection pump. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 1 (Orange wire) on MAP sensor harness connector. If voltage is 4.5 volts or less, go to next step. If voltage is greater than 4.5 volts, replace WIF sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 6. Turn ignition off. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Using DVOM, measure resistance between ground and terminal No. 10 (Orange wire) on ECM harness connector. If resistance is 5 ohms or greater, go to next step. If resistance is less than 5 ohms, repair short to ground in Orange wire between ECM, MAP sensor, engine oil pressure sensor, WIF sensor and CMP sensor. 7. Ensure ECM harness connector and MAP sensor harness connector are still disconnected. Using DVOM, measure resistance of Orange wire between terminal No. 1 on MAP sensor harness connector and terminal No. 10 on ECM harness connector. If resistance is less than 5 ohms, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If resistance is 5 ohms or greater, repair open in Orange wire between MAP sensor and ECM. 8. Problem is intermittent. Inspect MAP sensor harness connector and ECM harness connector for corroded, pushed out or damaged terminals. Inspect wiring harness and connectors between MAP sensor and ECM for chafed, pierced or partially broken wires. If terminals are not corroded, pushed out or damaged and wiring is okay, check for technical service bulletins that may apply. If terminals are corroded, pushed out or damaged, or wiring is damaged, repair as necessary.

DTC P1475: AUXILIARY 5 VOLT OUTPUT TOO HIGH Monitor & Set Conditions Auxiliary 5-volt output circuit is monitored with ignition on engine off, and with engine running. DTC may set if voltage on 5-volt sensor supply circuit exceeds 5.7 volts for 5 seconds. Possible Causes 5-volt Supply Circuit Shorted To Battery Voltage Wiring Harness Or Connector Broken, Bent Or Pushed Out Terminals ECM Testing 1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1475 is displayed and not equal to zero, go to next step. If Good Trip Counter for DTC P1475 is displayed and equal to zero, go to step 3 . 2. Ensure ignition is on with engine off. At this time, DTC is intermittent. Using scan tool, determine if DTC matches FREEZE FRAME DTC. If DTC is not equal to FREEZE FRAME DTC, freeze frame DTC is a higher priority DTC and should be diagnosed before diagnosing DTC P1475. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If DTC is equal to FREEZE FRAME DTC, try to duplicate conditions recorded in FREEZE FRAME data. Start engine and allow engine to idle. Using scan tool in SENSORS, read Manifold Absolute Pressure (MAP) sensor voltage. If MAP sensor voltage is greater than 5.2 volts, go to next step. If MAP sensor voltage is 5.2 volts or less, go to step 4 . 3. Turn engine off. Disconnect MAP sensor harness connector. MAP sensor is located on driver's side rear corner of cylinder head. Check for poor connection/terminal contact at MAP sensor harness connector. Repair as necessary. Start engine and allow engine to idle. Using DVOM, measure voltage between ground and terminal No. 1 (Orange wire) on MAP sensor harness connector. If voltage is 5.2 volts or less, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If voltage is greater than 5.2 volts, repair short to voltage on Orange wire between MAP sensor and ECM. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. 4. Shut engine off. Turn ignition on with engine off. Using scan tool, monitor MAP sensor voltage while wiggling wiring harness and connectors between MAP sensor and ECM. MAP sensor is located on driver's side rear corner of cylinder head. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. If MAP sensor voltage does not change while wiggling wiring harness and connectors, go to next step. If MAP sensor voltage changes while wiggling harness and/or connectors, repair wiring or connectors as necessary. 5. Problem is intermittent. Inspect MAP sensor harness connector and ECM harness connector for corroded, pushed out or damaged terminals. Inspect wiring harness and connectors between MAP sensor and ECM for chafed, pierced or partially broken wires. If terminals are not corroded, pushed out or damaged and wiring is okay, check for technical service bulletins that may apply. If terminals are corroded, pushed out or damaged, or wiring is damaged, repair as necessary.

DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM 1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is not displayed and equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is displayed and equal to zero, go to step 4 . 2. Ensure ignition is on with engine off. Using scan tool, check for DTCs. Check that displayed DTC matches the FREEZE FRAME DTC. If DTCs displayed are the same, go to next step. If DTCs displayed are not the same, perform procedures for FREEZE FRAME DTC. 3. Using scan tool, check for DTCs and record FREEZE FRAME data. Try to duplicate conditions recorded in FREEZE FRAME data. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter changes to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter does not change to zero, go to step 7 . 4. Turn ignition off. Remove ASD relay from power distribution center. See Fig. 54 . Power distribution center is located at driver's side front corner of engine compartment. Note cavities in power distribution center for ASD relay. See Fig. 54 . Using voltmeter, check voltage at cavity No. 30 (Red/Light Blue wire) in power distribution center for ASD relay. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open between battery, fuse No. 6 (30-amp) and Red/Light Blue wire between fuse No. 6 in power distribution center and cavity No. 30 in power distribution center for ASD relay. Perform TEST VER-2A . 5. Ensure ignition is off and ASD relay is still removed from power distribution center. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between cavity No. 87 (Dark Green/Orange wire) in power distribution center for ASD relay and terminal No. 12 (Dark Green/Orange wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Green/Orange wire between PCM and cavity No. 87 in power distribution center for ASD relay. Perform TEST VER-2A . 6. Ensure ignition is off. Install a substitute ASD relay. Using scan tool, clear DTCs. Start engine and allow engine to idle. Using scan tool, check for DTCs. If DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM exists, replace PCM. Perform TEST VER-2A . If DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM does not exist, replace original ASD relay. Perform TEST VER-2A . 7. Using scan tool, clear DTCs. Start engine and allow engine to idle. Wiggle wiring harness and connectors between ASD relay and PCM. The ASD relay is located in power distribution center at driver's side front corner of engine compartment. See Fig. 54 . PCM is located at passenger's side rear corner of engine compartment. Using scan tool, check for DTCs. If DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM does not exist, go to next step. If DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM exists, repair wiring harness or connectors between ASD relay and PCM that caused DTC. Perform TEST VER-2A . 8. Shut engine off. At this time, conditions required for DTC to be stored are not present. Inspect wiring harness and connectors between ASD relay and PCM. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-2A . 9. Problem is intermittent. Inspect PCM connectors for corroded, pushed out or damaged terminals. Inspect wiring harness and connectors between ASD relay and PCM for chafed, pierced or partially broken wires. If terminals are not corroded, pushed out or damaged and wiring is okay, check for Technical Service Bulletins (TSBs) that may apply. If terminals are corroded, pushed out or damaged, or wiring is damaged, repair as necessary. Perform TEST VER-2A .

DTC P1388: AUTO SHUTDOWN RELAY CONTROL CIRCUIT 1. Turn ignition on with engine off. Using scan tool, actuate ASD relay. Listen for clicking sound at ASD relay. The ASD relay is located in power distribution center at driver's side front corner of engine compartment. See Fig. 54 . If clicking sound is heard at ASD relay, go to next step. If clicking sound is not heard at ASD relay, go to step 4 . 2. Stop actuation of ASD relay. Inspect wiring harness and connectors between ASD relay and PCM. PCM is located at passenger's side rear corner of engine compartment. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-2A . 3. Start engine and allow engine to idle. Wiggle wiring harness and connectors between ASD relay and PCM. If engine does not stall while wiggling wiring harness and connectors, test is complete. If engine stalls while wiggling wiring harness and connectors, repair wiring or connectors as necessary that cause engine to stall. Perform TEST VER-2A . 4. Turn ignition off. Remove ASD relay from power distribution center. Note cavities in power distribution center for ASD relay. See Fig. 54 . Turn ignition on with engine off. Using voltmeter, check voltage at cavity No. 86 (Light Green/Black wire) in power distribution center for ASD relay. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open between ignition switch, fuse No. 9 (10-amp) and Light Green/Black wire between fuse No. 9 and cavity No. 86 in power distribution center for ASD relay. Fuse No. 9 is located in junction block on end of driver's side of instrument panel, near door opening. Perform TEST VER-2A . 5. Note which terminals on ASD relay correspond with cavities in power distribution center. See Fig. 54 . Using ohmmeter, check resistance between terminals on ASD relay that correspond with cavities No. 85 and 86 in power distribution center. If resistance is less than 100 ohms, go to next step. If resistance is 100 ohms or more, replace ASD relay. Perform TEST VER-2A . 6. Ensure ignition is off and ASD relay is still removed from power distribution center. Disconnect PCM connectors. PCM is located at passenger's side rear corner of engine compartment. Using ohmmeter, check resistance between cavity No. 85 (Dark Blue/Yellow wire) in power distribution center for ASD relay and terminal No. 3 (Dark Blue/Yellow wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Blue/Yellow wire between PCM and cavity No. 85 in power distribution center for ASD relay. Perform TEST VER-2A . 7. Ensure ASD relay is still removed from power distribution center and PCM connectors are still disconnected. Using ohmmeter, check resistance between ground and terminal No. 3 (Dark Blue/Yellow wire) on PCM connector C3. If resistance is 5 ohms or more, replace PCM. Perform TEST VER-2A . If resistance is less than 5 ohms, repair short to ground on Dark Blue/Yellow wire between PCM and cavity No. 85 in power distribution center for ASD relay. Perform TEST VER-2A .

DTC P1295: ACCELERATOR POSITION SENSOR (APPS) SUPPLY VOLTAGE TOO LOW Monitor & Set Conditions Accelerator Pedal Position Sensor (APPS) supply voltage is monitored when engine is running. DTC may be stored if low APPS signal circuit voltage exists, or low voltage is detected between Engine Control Module (ECM) and Powertrain Control Module (PCM). Possible Causes APPS APPS Supply Circuit Short To Ground APPS Shorted To Sensor Ground APPS Shorted APPS Supply Circuit Open ECM Testing 1. Turn ignition off. Disconnect APPS harness connector. APPS is located on bracket, just above fuel injection pump. Check for poor connection/terminal contact at APPS harness connector. Repair as necessary. Using DVOM, measure resistance between ground and terminal No. 5 (Dark Blue/White wire) on APPS harness connector. This is the APPS sensor supply wire and goes from terminal No. 5 on APPS harness connector to terminal No. 31 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, go to step 5 2. Turn ignition on. Ensure APPS harness connector is still disconnected. Using DVOM, measure voltage between ground and terminal No. 5 (Dark Blue/White wire) on APPS harness connector. If voltage is 4.5 volts or less, go to next step. If voltage is greater than 4.5 volts, replace APPS. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 3. Ensure APPS harness connector is still disconnected. Turn ignition off. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Using DVOM, measure resistance between ground and terminal No. 5 (Dark Blue/White wire) on APPS harness connector. If resistance is 5 ohms or greater, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/White wire between ECM and APPS. 4. Using DVOM, measure resistance between terminal No. 5 (Dark Blue/White wire) and terminal No. 11 (Black/Light Blue wire) on APPS connector. The Black/Light Blue wire is the sensor ground circuit. If resistance is 5 ohms or less, repair short between Dark Blue/White and Black/Light Blue wires. If resistance is greater than 5 ohms, replace and program ECM. See appropriate REMOVAL, OVERHAUL& INSTALLATION article. 5. Ensure APPS harness connector is still disconnected. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 5 (Dark Blue/White wire) on APPS connector. If voltage is 4.5 volts or less, go to next step. If voltage is greater than 4.5 volts, replace APPS. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 6. Turn ignition off. Ensure APPS harness connector is still disconnected. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Measure resistance of Dark Blue/White wire between terminal No. 5 on APPS harness connector and terminal No. 31 on ECM harness connector. If resistance is less than 5 ohms, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If resistance is 5 ohms or greater, repair open in Dark Blue/White wire between APPS and ECM.

DTC P1291: NO TEMPERATURE RISE SEEN FROM INTAKE AIR HEATERS Monitor & Set Conditions Temperature rise from intake air heaters is monitored for first 15 seconds of engine operation. DTC may be stored if initial Intake Air Temperature (IAT) sensor reading is 0-66°F (-17.8 to 18.8°C), Battery Temperature Sensor (BTS) and IAT sensor are within 10°F of each other, time between end of preheat and engine run state is less than 30 seconds, engine is cranked for less than 5 seconds before engine starts, preheat is completed before engine starts, post-heat is active and no IAT sensor or intake air heater relay DTCs exist. Possible Causes Good Trip Counter Change To Zero DTC Equal To Freeze Frame Technical Service Bulletins (TSB) Or Hotline Bulletins Battery Cable High Resistance Intake Air Heater Feed High Resistance Intake Air Heater No. 2 Relay No. 2 Intake Air Heater No. 1 Intake Air Heater Feed High Resistance Intake Air Heater No. 1 Relay No. 1 Intake Air Heater Testing 1. Turn ignition on with engine off. Using DRBIII(R) scan tool, check for DTCs. If Good Trip Counter for DTC P1291 is displayed and equal to zero, go to next step. If Good Trip Counter for DTC P1291 is displayed and not equal to zero, go to step 5 . 2. Ensure ignition is on with engine off. Using DVOM, check and record voltage across battery terminals. Continue monitoring battery voltage while using scan tool to briefly actuate intake air heater No. 1. DO NOT actuate intake air heater No. 1 for any longer than possible, as intake air heater draws a large amount of current. Stop actuation of intake air heater No. 1. If battery voltage drops .5 volt or greater when intake air heater No. 1 is actuated, go to next step. If battery voltage drops less than .5 volt when intake air heater No. 1 was actuated, go to step 13 . 3. Ensure ignition is on with engine off. Using DVOM, check and record voltage across battery terminals. Continue monitoring battery voltage while using scan tool to briefly actuate intake air heater No. 2. DO NOT actuate intake air heater No. 2 for any longer than possible, as intake air heater draws a large amount of current. Stop actuation of intake air heater No. 2. If battery voltage drops .5 volt or greater when intake air heater No. 2 is actuated, go to next step. If battery voltage drops less than .5 volt when intake air heater No. 2 was actuated, go to step 10 . 4. Ensure ignition is on with engine off. Using scan tool, check for DTCs and record FREEZE FRAME data. Try to duplicate conditions recorded in FREEZE FRAME data. Using scan tool, check for DTCs. If Good Trip Counter for DTC P1291 changes to zero, go to step 9 . If Good Trip Counter for DTC P1291 does not change to zero, conditions required for DTC to be stored are not present at this time. Possible causes are IAT sensor, intake air heater relay, intake air heater element or high resistance cables. Test is complete. 5. Ensure ignition is on with engine off. Using scan tool, determine if DTC matches FREEZE FRAME DTC. If DTC is equal to FREEZE FRAME DTC, go to next step. If DTC is not equal to FREEZE FRAME DTC, freeze frame DTC is a higher priority DTC and should be diagnosed before diagnosing DTC P1291. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . 6. Ensure ignition is on with engine off. Using scan tool, check for DTCs and record FREEZE FRAME data. Try to duplicate conditions recorded in FREEZE FRAME data. Using scan tool, check for DTCs. If Good Trip Counter for DTC P1291 changes to zero, go to next step. If Good Trip Counter for DTC P1291 does not change to zero, conditions required for DTC to be stored are not present at this time. Possible causes are IAT sensor, intake air heater relay, intake air heater element or high resistance cables. Test is complete. 7. Using DVOM, check and record voltage across battery terminals. Continue monitoring battery voltage while using scan tool to briefly actuate intake air heater No. 1. DO NOT actuate intake air heater No. 1 for any longer than possible, as intake air heater draws a large amount of current. Stop actuation of intake air heater No. 1. If battery voltage drops .5 volt or greater when intake air heater No. 1 is actuated, go to next step. If battery voltage drops less than .5 volt when intake air heater No. 1 was actuated, go to step 13 . 8. Using DVOM, check and record voltage across battery terminals. Continue monitoring battery voltage while using scan tool to briefly actuate intake air heater No. 2. DO NOT actuate intake air heater No. 2 for any longer than possible, as intake air heater draws a large amount of current. Stop actuation of intake air heater No. 2. If battery voltage drops .5 volt or greater when intake air heater No. 2 is actuated, go to next step. If battery voltage drops less than .5 volt when intake air heater No. 2 was actuated, go to step 10 . 9. Problem is intermittent. Turn ignition off. Inspect Engine Control Module (ECM) harness connector for corroded, pushed out or damaged terminals. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Inspect wiring harness and connectors between ECM and intake air heater relays for chafed, pierced or partially broken wires. Inspect battery cables between batteries and intake air heater relays, and cables between intake air heater relays and intake air heater assembly. Intake air heater relays are located on bracket near driver's side battery. Intake air heater assembly is located on top of intake manifold. If terminals are not corroded, pushed out or damaged and wiring and cables are okay, check for Technical Service Bulletins (TSB) that may apply. If terminals are corroded, pushed out or damaged, or wiring or cables are damaged, repair as necessary. 10. Ensure ignition is on with engine off. Perform voltage drop test on battery cable that goes from battery to intake air heater relay No. 2. Intake air heater relay No. 2 is located on bracket near driver's side battery. If voltage drop on battery cable is .1 volt or less, go to next step. If voltage drop on battery cable is greater than .1 volt, replace battery cable. 11. Ensure ignition is on with engine off. Check cable that goes from intake air heater relay No. 2 to intake air heater No. 2 for excessive resistance by checking voltage drop on the cable. Intake air heaters No. 1 and 2 are incorporated into intake air heater assembly located on top of intake manifold. Intake air heaters may also be referred to as intake manifold air heaters. If voltage drop on cable is .1 volt or less, go to next step. If voltage drop on cable is greater than .1 volt, replace cable. 12. Ensure ignition is on with engine off. Connect DVOM between ground and output terminal on intake air heater relay No. 2. This is the terminal that the cable is attached to that goes to intake air heater No. 2. If voltage is greater than 12 volts, intake air heater No. 2 is defective. Replace intake air heater assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If voltage is 12 volts or less, replace intake air heater relay No. 2. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. 13. Ensure ignition is on with engine off. Perform voltage drop test on battery cable that goes from battery to intake air heater relay No. 1. Intake air heater relay No. 1 is located on bracket near driver's side battery. If voltage drop on battery cable is .1 volt or less, go to next step. If voltage drop on battery cable is greater than .1 volt, replace battery cable. 14. Ensure ignition is on with engine off. Check cable that goes from intake air heater relay No. 1 to intake air heater No. 1 for excessive resistance by checking voltage drop on the cable. Intake air heaters No. 1 and 2 are incorporated into intake air heater assembly located on top of intake manifold. Intake air heaters may also be referred to as intake manifold air heaters. If voltage drop on cable is .1 volt or less, go to next step. If voltage drop on cable is greater than .1 volt, replace cable. 15. Ensure ignition is on with engine off. Connect DVOM between ground and output terminal on intake air heater relay No. 1. This is the terminal that the cable is attached to that goes to intake air heater No. 1. If voltage is greater than 12 volts, intake air heater No. 1 is defective. Replace intake air heater assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If voltage is 12 volts or less, replace intake air heater relay No. 1. See appropriate REMOVAL, OVERHAUL & INSTALLATION

DTC P1287: FUEL INJECTION PUMP CONTROLLER SUPPLY VOLTAGE LOW Monitor & Set Conditions Fuel injection pump controller supply voltage is monitored when ignition is on. DTC may be stored if low voltage exists. Possible Causes Charging System Not Operating Properly Testing Check that charging system is operating properly. If charging system operates properly, test is complete. If charging system does not operate properly, perform CHARGING SYSTEM test under MISCELLANEOUS CONTROLS in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.

DTC P1286: ACCELERATOR POSITION SENSOR (APPS) SUPPLY VOLTAGE TOO HIGH Monitor & Set Conditions Accelerator Pedal Position Sensor (APPS) supply voltage is monitored when engine is running. DTC may be stored if Engine Control Module (ECM) senses high voltage on APPS supply circuit. Possible Causes APPS Supply Circuit Shorted To Voltage APPS Shorted To Voltage APPS Signal Circuit Shorted To Voltage APPS Signal Shorted To Voltage APPS APPS Return Circuit Open APPS Signal Circuit Open APPS Supply Circuit Open ECM Testing 1. Turn ignition off. Disconnect APPS harness connector. APPS is located on bracket, just above fuel injection pump. Check for poor connection/terminal contact at APPS harness connector. Repair as necessary. Start engine and allow engine to idle. Using DVOM, measure voltage between ground and terminal No. 5 (Dark Blue/White wire) on APPS harness connector. If voltage is greater than 5.5 volts, go to next step. If voltage is 5.5 volts or less, go to step 4 . 2. Shut engine off. Ensure APPS harness connector is still disconnected. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 5 (Dark Blue/White wire) on APPS harness connector. If voltage is greater than 5.5 volts, go to next step. If voltage is 5.5 volts or less, repair short to voltage on Dark Blue/White wire between APPS and ECM when engine is running. 3. Turn ignition off. Ensure APPS harness connector is still disconnected. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Check for poor connection/terminal contact at ECM harness connector. Repair as necessary. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 5 (Dark Blue/White wire) on APPS harness connector. If voltage is 5.5 volts or less, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. If voltage is greater than 5.5 volts, repair short to voltage on Dark Blue/White wire between APPS and ECM. 4. Turn ignition off. Using DVOM, measure voltage between ground and terminal No. 3 (Light Blue/Black wire) on APPS harness connector. If voltage is greater than 5.5 volts, go to next step. If voltage is 5.5 volts or less, go to step 7 . 5. Ensure APPS harness connector is still disconnected. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 3 (Light Blue/Black wire) on APPS harness connector. If voltage is greater than 5.5 volts, go to next step. If voltage is 5.5 volts or less, repair short to voltage on Light Blue/Black wire between APPS and ECM. 6. Turn ignition off. Ensure APPS harness connector is still disconnected. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Check for poor connection/terminal contact at ECM harness connector. Repair as necessary. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 3 (Light Blue/Black wire) on APPS harness connector. If voltage is 5.5 volts or less, replace and greater than 5.5 volts, repair short to voltage on Light Blue/Black wire between APPS and ECM. 7. Ensure ignition is off. Ensure APPS harness connector is still disconnected. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Check for poor connection/terminal contact at ECM harness connector. Repair as necessary. Measure resistance of Dark Blue/White wire between terminal No. 5 on APPS harness connector and terminal No. 31 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Dark Blue/White wire between APPS and ECM. 8. Ensure ignition is off. Ensure APPS harness connector and ECM harness connector are still disconnected. Measure resistance of Black/Yellow wire between terminal No. 4 on APPS harness connector and terminal No. 32 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Black/Yellow wire between APPS and ECM. 9. Ensure ignition is off. Ensure APPS harness connector and ECM harness connector are still disconnected. Measure resistance of Light Blue/Black wire between terminal No. 3 on APPS harness connector and terminal No. 25 on ECM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Light Blue/Black wire between APPS and ECM. 10. Replace APPS. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.

DTC P1285: FUEL INJECTION PUMP CONTROLLER ALWAYS ON Monitor & Set Conditions Fuel Pump Control Module (FPCM) is monitored with ignition off and less than 600 RPM. DTC may set when more than 4 CAN BUS messages are received from FPCM while key is off and RPM is less than 600. Possible Causes Fuel Injection Pump Relay Stuck On Testing Turn ignition off. Remove fuel pump relay from Power Distribution Center (PDC). PDC is located at driver's side front corner of engine compartment. Fuel injection pump relay may also be referred to as fuel relay. Note which terminals on fuel pump relay correspond with cavities in PDC. Using DVOM, measure resistance between terminals on fuel pump relay that correspond with cavities No. 30 and 87 in PDC. If resistance is 5 ohms or greater, test is complete. If resistance is less than 5 ohms, replace fuel pump relay.

DTC P1284: FUEL INJECTOR PUMP BATTERY VOLT OUT-OF-RANGE 1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is not displayed and equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is displayed and equal to zero, replace fuel injection pump. Perform TEST VER-5A . 2. At this time, conditions required for DTC to be stored are not present. Ensure ignition is on with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions displayed in FREEZE FRAME data parameters while noting DTC SPECIFIC GOOD TRIP COUNTER. If DTC SPECIFIC GOOD TRIP counter does not change to zero, test is complete. If DTC SPECIFIC GOOD TRIP counter changes to zero, replace fuel injection pump. Perform TEST VER-5A .

DTC P1283: IDLE SELECT SIGNAL INVALID Monitor & Set Conditions Idle select switch signal is monitored when ignition is on. DTC may be stored if Fuel Pump Control Module (FPCM) detects a false low idle select signal from ECM. FPCM is incorporated into fuel injection pump and may also be referred to as the fuel injection pump when referencing to wiring diagram. Possible Causes Low Idle Select Circuit Open Low Idle Select Circuit Shorted To Ground ECM - Low Idle Select Circuit Low Idle Select Circuit Short To Voltage ECM Low Idle Select Circuit Shorted To Ground In ECM Testing 1. Turn ignition off. Disconnect Fuel Pump Control Module (FPCM) harness connector. FPCM connector is located on end of fuel injection pump. Disconnect ECM harness connector. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. Check for poor connection/terminal contact at ECM harness connector. Repair as necessary. Using DVOM, measure resistance of Violet/Orange wire between terminal No. 4 on FPCM harness connector and terminal No. 34 on ECM harness connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Violet/Orange wire between FPCM and ECM. 2. Ensure ignition is off. Ensure FPCM connector and ECM connector are still disconnected. Using DVOM, measure resistance between ground and terminal No. 34 (Violet/Orange wire) at ECM harness connector. If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in Violet/Orange wire between FPCM and ECM. 3. Ensure ignition is off and FPCM harness connector is still disconnected. Reinstall ECM harness connector. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 4 (Violet/Orange wire) on FPCM harness connector. If voltage is 6 volts or less, go to next step. If voltage is greater than 6 volts, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. 4. Turn ignition off. Ensure FPCM harness connector is still disconnected. Disconnect ECM harness connector. Turn ignition on with engine off. Using DVOM, measure voltage between ground and terminal No. 4 (Violet/Orange wire) on FPCM harness connector. If voltage is 6 volts or less, go to next step. If voltage is greater than 6 volts, repair short to voltage on Violet/Orange wire between FPCM and ECM. 5. Turn ignition off. Ensure FPCM harness connector is still disconnected. Reconnect ECM harness connector. Connect DVOM between ground and terminal No. 4 (Violet/Orange wire) on FPCM harness connector. If resistance is 5 ohms or less, test is complete. If resistance is greater than 5 ohms, replace and program ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.