Mopar1973Man

P0643 HIGH VOLTAGE AT THE #2 SENSOR SUPPLY CIRCUIT When Monitored and Set Condition: When Monitored: With the key on. Set Condition: Voltage detected on the #2 sensor supply circuit was above a calibrated value. POSSIBLE CAUSES FAN CLUTCH ASSEMBLY (F856) 5-VOLT SHORTED TO VOLTAGE INTERMITTENT CONDITION ECM DIAGNOSTIC PROCEDURE Disconnect the Fan clutch harness connector. With the DRBIII®, read DTCs. Did P0483 set? Yes --> Replace the Fan clutch assembly. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 2 Disconnect the ECM harness connectors. Disconnect the Fan harness connector. NOTE: Check connectors - Clean/repair as necessary. Measure the voltage between the fan speed sensor (F856) 5-volt supply circuit and battery negative. Is the voltage greater than 1 volt? Yes --> Repair the (F856) 5-volt supply shorted to voltage. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 3 Turn the ignition off. Reconnect the ECM harness connectors. Turn the ignition on. Measure the voltage between the (F856) 5-volt supply circuit in the sensor harness connector and battery negative. Is the voltage greater than 6 volts? Yes --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

P0642 LOW VOLTAGE AT THE #2 SENSOR SUPPLY CIRCUIT When Monitored and Set Condition: When Monitored: With the key on. Set Condition: Voltage detected on the #2 sensor supply circuit is below a calibrated value. POSSIBLE CAUSES FAN CLUTCH ASSEMBLY (F856) 5-VOLT SHORTED TO GROUND (F856) 5-VOLT SUPPLY SHORTED TO ANOTHER CIRCUIT FAN DTC INTERMITTENT CONDITION ECM DIAGNOSTIC PROCEDURE Disconnect the Fan clutch harness connector. NOTE: Check connectors - Clean/repair as necessary. With the DRBIII®, read DTCs. Did P0483 set? Yes --> Replace the Fan clutch assembly. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 2 Turn the ignition off. Disconnect the ECM harness connector. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance between the (F856) #2 5-volt supply (fan speed sensor power) circuit in the sensor harness connector and battery negative. Is the resistance greater than 100k Ohms? Yes --> Go To 3 No --> Repair the #2 (F856) 5-volt supply shorted to ground. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Measure the resistance between the sensor (F856) #2 5-volt supply (fan speed sensor power) circuit in the ECM harness connector to all other circuits in the ECM harness connectors Is the resistance greater than 100k Ohms? Yes --> Go To 4 No --> Repair the 5-volt supply shorted to another circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Reconnect the ECM harness connectors. Reconnect the disconnected Fan harness connector. Turn the ignition on. With the DRBIII®, read DTCs. Is DTC P0483 set? Yes --> Repair the Fan DTC. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 5 Turn the ignition off. Disconnect the Fan harness connector. Turn the ignition on. Measure the voltage between the sensor (F856) #2 5-volt supply (fan speed sensor power) circuit at the fan clutch harness connector and the fan speed sensor ground. Is the voltage between 4.5 and 5.5 volts? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

P0633 SKIM SECRET KEY NOT ENTERED When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: The SKIM secret key was not calibrated into the ECM. POSSIBLE CAUSES IMPROPER IGNITION KEY IS BEING USED SKIM DTC'S SKIM NOT CALIBRATED PROPERLY DIAGNOSTIC PROCEDURE With the DRBIII®, read SKIM DTCs. Are any SKIM DTCs present? Yes --> Repair all SKIM DTCs first. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 2 Verify that the proper ignition key is in the ignition lock on the steering column. Are the proper keys being used? Yes --> Go To 3 No --> Use the proper key for the vehicle. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Using the DRBIII®, recalibrate the ECM with the proper SKIM secret key. With the DRBIII®, erase DTCs. Cycle the ignition switch from on to off to on. With the DRBIII®, read DTCs. Did the DTC reset? Yes --> Test Complete. No --> Verify information is correct and replace ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

P0630 VIN NOT ENTERED ERROR When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: The VIN was not calibrated into the ECM. POSSIBLE CAUSES VIN NOT CALIBRATED INTO ECM DIAGNOSTIC PROCEDURE Using the DRBIII®, recalibrate the ECM with the proper VIN. Did the DTC P0630 reset? Yes --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Test Complete.

P0629 HIGH VOLTAGE DETECTED AT THE FUEL LIFT PUMP When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: The commanded signal to the lift pump does not match the feedback signal from the lift pump. POSSIBLE CAUSES LOOSE CONNECTION (K62) SUPPLY CIRCUIT SHORTED TO VOLTAGE (K62) SUPPLY CIRCUIT SHORTED LIFT PUMP ECM DIAGNOSTIC PROCEDURE With the DRBIII®, in system test actuate the lift pump. Does the lift pump run? Yes --> Go To 2 No --> Go To 5 Lift pump actuation still running. While the lift pump is running, wiggle the wiring harness and connectors throughout the circuit. Does this interrupt the pump operation? Yes --> Repair the loose connection. No --> Go To 3 Disconnect the ECM harness connectors. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance between the lift pump (K62) supply circuit of the lift pump connector and battery negative. Is the resistance greater than 100k Ohms? Yes --> Go To 4 No --> Repair the (K62) supply circuit shorted to voltage. Measure the resistance between the lift pump (K62) supply circuit and all other circuits in the ECM harness connectors. Is the resistance greater than 100k Ohms? Yes --> Go To 5 No --> Repair the (K62) supply circuit shorted to another circuit. Reconnect the disconnected Lift pump harness connector. Reconnect the ECM harness connectors. Turn the ignition on. With the DRBIII®, read DTCs while disconnecting the lift pump. Did P0628 set? Yes --> Replace the lift pump. No --> Replace the ECM

P0628 LOW VOLTAGE DETECTED AT THE FUEL LIFT PUMP When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: The voltage detected on the Fuel Lift Pump is above a calibrated value for a calibrated amount on time. POSSIBLE CAUSES LOOSE CONNECTION GROUND CIRCUIT OPEN LIFT PUMP SHORTED TO VOLTAGE LIFT PUMP ECM DIAGNOSTIC PROCEDURE With the DRBIII®, in system test actuate the lift pump. Does the lift pump run? Yes --> Go To 2 No --> Go To 3 Lift pump actuation still running. While the lift pump is running, wiggle the wiring harness and connectors throughout the circuit. Does this interrupt the pump operation? Yes --> Repair the loose connection. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 3 Disconnect the ECM harness connectors. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the lift pump (K62) supply circuit between the ECM harness connector and the lift pump harness connector. Is the resistance less than 1 Ohms? Yes --> Go To 4 No --> Test Complete. Measure the resistance of the ground circuit between the lift pump connector and battery negative. Is the resistance less than 1 Ohms? Yes --> Go To 5 No --> Repair the open ground circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Measure the voltage between the supply and ground circuits of the lift pump connector. Is the voltage greater than 1 volt? Yes --> Repair the lift pump circuits shorted to voltage. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Go To 6 Reconnect the ECM harness connectors. Connect a jumper wire between the (K62) supply circuit and ground circuit of the lift pump harness connector. Turn the ignition on. With the DRBIII®, read DTCs. Did DTC P0628 set? Yes --> Replace the lift pump. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Replace the ECM. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

P0622 GENERATOR FIELD NOT SWITCHING PROPERLY When Monitored and Set Condition: When Monitored: When the ignition is on. Set Condition: The feedback signal does not match the commanded signal for the voltage regulator. POSSIBLE CAUSES GENERATOR OPEN DRIVER CIRCUIT GEN SOURCE SHORTED TO BATTERY NEGATIVE (K20) FIELD DRIVER CIRCUIT SHORTED TO VOLTAGE GEN SOURCE OPEN ECM DIAGNOSTIC PROCEDURE Turn the ignition off. Disconnect the Generator field harness connector. Check connectors - Clean/repair as necessary. Measure the resistance between the generator field terminals. Is the resistance between.5 and 15 Ohms? Yes --> Go To 2 No --> Replace the Generator. Disconnect the ECM harness connectors. Check connectors - Clean/repair as necessary. Measure the resistance of the generator driver wire between the generator harness connector and the ECM harness connector. Is the resistance less than 10 ohms. Yes --> Go To 3 No --> Repair the open driver circuit. Measure the resistance of the generator source circuit between the generator harness connector and battery negative. Is the resistance less than 10 ohms. Yes --> Repair the Gen source shorted to Battery negative. No --> Go To 4 Measure the voltage between the (K20) generator field driver circuit in the generator harness connector and battery negative. Is the voltage greater than 1 volt? Yes --> Repair the (K20) Generator field driver circuit shorted to voltage. No --> Go To 5 Measure voltage of the Gen source circuit at the generator harness connector. Is voltage within one volt of battery voltage? Yes --> Replace the ECM. No --> Repair the open or high resistance of Gen source circuit.

P0613 INTERNAL TCM When Monitored and Set Condition: When Monitored: Continuously with the ignition on. Set Condition: Whenever the PCM detects an internal controller problem, POSSIBLE CAUSES POWER OR GROUND CIRCUIT POWERTRAIN CONTROL MODULE DIAGNOSTIC PROCEDURE Using the schematics as a guide, inspect the wiring and connectors specific to the PCM and Transmission Control Relay circuits. NOTE: Pay particular attention to all power and ground circuits pertaining to the PCM. Due to the integration of the Powertrain and Transmission Control Modules, the transmission part of the PCM has its own specific power and ground circuits. Wiggle the wires while checking for shorted and open circuits. Check for any applicable TSB's that may apply. CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS. Were there any problems found? Yes --> Repair the power and/or ground circuits to the PCM and Transmission Control Relay as necessary. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 2 Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, view repair. Repair Replace the Powertrain Control Module and perform STANDARD PROCEDURE - TCM QUICK LEARN . Refer to ELECTRONIC CONTROL MODULES . Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 .

P0607 ECM INTERNAL FAILURE When Monitored and Set Condition: When Monitored: With the key on or engine running Set Condition: ECM had detected internal failures. POSSIBLE CAUSES ECM DIAGNOSTIC PROCEDURE Turn the ignition on. NOTE: This DTC is caused by an internal Engine Control Module failure. Repairs are not possible to the ECM. Is the DTC P0606 set? Yes --> Replace and program the ECM in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Test Complete.

P0606 ECM HARDWARE ERROR When Monitored and Set Condition: When Monitored: With the key on or engine running. Set Condition: ECM had detected internal failures. POSSIBLE CAUSES ECM DIAGNOSTIC PROCEDURE Turn the ignition on. NOTE: This DTC is caused by an internal Engine Control Module failure. Repairs are not possible to the ECM. With the DRBIII®, erase DTCs. Is the DTC still set? Yes --> Replace and program the ECM in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). No --> Test Complete.

P0605 INTERNAL TCM When Monitored and Set Condition: When Monitored: Continuously with the ignition on. Set Condition: Whenever the PCM detects an internal controller problem. POSSIBLE CAUSES POWER OR GROUND CIRCUIT POWERTRAIN CONTROL MODULE DIAGNOSTIC PROCEDURE Using the schematics as a guide, inspect the wiring and connectors specific to the PCM and Transmission Control Relay circuits. NOTE: Pay particular attention to all power and ground circuits pertaining to the PCM. Due to the integration of the Powertrain and Transmission Control Modules, the transmission part of the PCM has its own specific power and ground circuits.Wiggle the wires while checking for shorted and open circuits. Check for any applicable TSB's that may apply. CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS. Were there any problems found? Yes --> Repair the power and/or ground circuits to the PCM and Transmission Control Relay as necessary. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 2 Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, view repair. Repair Replace and program the Powertrain Control Module. WITH THE DRBIII(R) PERFORM STANDARD PROCEDURE - TCM QUICK LEARN . Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 .

P0604 INTERNAL TCM When Monitored and Set Condition: When Monitored: Continuously with the ignition on. Set Condition: Whenever the PCM detects an internal controller problem. POSSIBLE CAUSES POWER OR GROUND CIRCUIT POWERTRAIN CONTROL MODULE DIAGNOSTIC PROCEDURE Using the schematics as a guide, inspect the wiring and connectors specific to the PCM and Transmission Control Relay circuits. NOTE: Pay particular attention to all power and ground circuits pertaining to the PCM. Due to the integration of the Powertrain and Transmission Control Modules, the transmission part of the PCM has its own specific power and ground circuits. Wiggle the wires while checking for shorted and open circuits. Check for any applicable TSB's that may apply. CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS. Were there any problems found? Yes --> Repair the power and/or ground circuits to the PCM and Transmission Control Relay as necessary. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 2 Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, view repair. Repair Replace the Powertrain Control Module and perform STANDARD PROCEDURE - TCM QUICK LEARN . Refer to ELECTRONIC CONTROL MODULES . Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1

P0604 ECM SOFTWARE ERROR When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: Internal ECM software error. POSSIBLE CAUSES REFLASH ECM ECM DIAGNOSTIC PROCEDURE Using the DRBIII®, reflash the module with latest calibration Was the flash successful? Yes --> Go To 2 No --> Replace the ECM. Run the engine for one minute and shut off. With the DRBIII®, read DTCs. Did P0604 set? Yes --> Replace the ECM. No --> Test Complete.

P0602 CONTROL MODULE PROGRAMMING ERROR When Monitored and Set Condition: When Monitored: Continuously Set Condition: The DTC will always light the MIL, and is designed to signal the technician that the controller still has generic software installed. POSSIBLE CAUSES ENGINE AND TRANSMISSION NEED TO BE PROGRAMMED PCM DIAGNOSTIC PROCEDURE NOTE: Controller is programmed with generic software and will not allow proper Powertrain operation. NOTE: This DTC can cause a no start condition in some vehicles. NOTE: Check controller power and grounds before proceeding. Ignition on, engine not running. With the DRBIII(R), erase DTCs. With the DRBIII(R) program the engine and transmission software. Start the engine. Allow the engine to reach normal operating temperature. With the DRBIII(R), read DTCs. Does the DTC reset? Yes --> Replace the Powertrain Control Module and perform STANDARD PROCEDURE - TCM QUICK LEARN . Refer to ELECTRONIC CONTROL MODULES . Note: Program both the engine and transmission software. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 . No --> The PCM has been successfully programmed. Test is complete. Perform (NGC) 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1 .

P0602 CHECKSUM ERROR When Monitored and Set Condition: When Monitored: While the ignition is on. Set Condition: A deviation between the ECM memory and a stored calibration. POSSIBLE CAUSES FLASH ECM ECM DIAGNOSTIC PROCEDURE Using the DRBIII®, reflash the ECM with the proper calibration for the particular truck. Is the flash successful? Yes --> Repair complete. No --> Go To 2 With the DRBIII®, read DTCs. Did P0602 set after the reflash? Yes --> Replace the ECM. No --> Test Complete.

P0596 HIGH VOLTAGE DETECTED AT THE S/C BRAKE SWITCH OUTPUT When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: The voltage detected on the Speed Control Servo is below a calibrated value for a calibrated amount on time. POSSIBLE CAUSES SPEED CONTROL SERVO ASSEMBLY (V32) S/C 12-VOLT SOURCE SHORTED TO OTHER CIRCUITS (V32) S/C BRAKE SWITCH OUTPUT SHORTED TO GROUND ECM INTERMITTENT CONDITION DIAGNOSTIC PROCEDURE Turn the ignition off. Disconnect the Speed control servo harness connector. NOTE: Check connectors - Clean/repair as necessary. Ignition on, engine not running. With the DRBIII®, actuate the S/C 12-volt source. Using a 12-volt test light connected to battery ground, check the S/C brake switch Output circuit in the Speed Control servo harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Replace the speed control servo assembly. No --> Go To 2 Turn the ignition off. Disconnect the ECM harness connector(s). NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the S/C brake switch output circuit between the Speed Control assembly connector and battery negative. Is the resistance greater than 100k Ohms? Yes --> Go To 3 No --> Repair the (V32) S/C brake switch output shorted to ground. Measure the resistance between the S/C 12-volt source circuit in the ECM harness connector and all other circuits in the ECM harness connectors. Is the resistance less than 100k Ohms? Yes --> Go To 4 No --> Repair the (V32) S/C 12-volt source circuit shorted to other circuit. Turn the ignition off. Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the S/C 12-volt source. Using a 12-volt test light connected to battery ground, check the S/C brake switch Output circuit in the Speed Control servo harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Test Complete. No --> Replace and program the ECM in accordance with the Service Information.

P0595 LOW VOLTAGE DETECTED AT THE S/C BRAKE SWITCH OUTPUT When Monitored and Set Condition: When Monitored: While the key is on. Set Condition: The voltage detected on the Cruise Control Servo is above a calibrated value for a calibrated amount on time. POSSIBLE CAUSES SPEED CONTROL SERVO (V32) S/C 12-VOLT SOURCE CIRCUIT OPEN GROUND CIRCUIT OPEN (V32) S/C 12-VOLT SOURCE SHORTED TO VOLTAGE (V32) S/C 12-VOLT SOURCE SHORTED TO OTHER CIRCUITS ECM INTERMITTENT CONDITION DIAGNOSTIC PROCEDURE Turn the ignition off. Disconnect the Speed Control Servo harness connector NOTE: Check connectors - Clean/repair as necessary. Turn the ignition on. With the DRBIII®, actuate the S/C 12 volt source. Using a 12-volt test light connected to ground, check the S/C 12-volt source circuit in the Speed Control Servo harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Go To 2 No --> Go To 3 Turn the ignition off. Disconnect the ECM harness connectors. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the ground circuit between the Speed control servo connector and battery negative. Is the resistance less than 10 ohms? Yes --> Replace the Speed control servo. No --> Repair the open ground circuit at the Cruise control servo harness connector. Turn the ignition off. Disconnect the ECM harness connectors. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the S/C 12-volt source circuit between the ECM harness connector and the Speed Control servo assembly harness connector. Is the resistance less than 10 Ohms? Yes --> Go To 4 No --> Repair the open (V32) 12-volt source circuit. Measure the voltage between the S/C 12-volt source circuit in the Speed Control servo assembly harness connector and battery negative. Is the voltage greater than 1 volt? Yes --> Repair the (V32) S/C 12-volt source circuit shorted to voltage. No --> Go To 5 Measure the resistance between the S/C 12-volt source circuit in the ECM harness connector and all other circuits in the ECM harness connectors. Is the resistance less than 10 Ohms? Yes --> Repair the (V32) S/C 12-volt source circuit shorted to other circuit. No --> Go To 6 Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the S/C 12-volt source. Using a 12-volt test light connected to ground, check the S/C brake switch output circuit in the Speed Control servo harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). No --> Replace and program the ECM in accordance with the Service Information.

P0588 HIGH VOLTAGE DETECTED AT THE SPEED CONTROL VENT DRIVER When Monitored and Set Condition: When Monitored: While the engine is running and the Speed control is set. Set Condition: The Speed control vent commanded state is on and the feedback state is off. POSSIBLE CAUSES SPEED CONTROL SERVO ASSEMBLY (V35) SPEED CONTROL VENT SHORTED TO VOLTAGE (V35) SPEED CONTROL VENT CIRCUIT SHORTED TO OTHER CIRCUITS ECM INTERMITTENT CONDITION SPEED CONTROL SERVO DIAGNOSTIC PROCEDURE Turn the ignition off. Disconnect the Speed control servo harness connector. NOTE: Check connectors - Clean/repair as necessary. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vacuum Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vacuum Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Replace the speed control servo assembly. No --> Go To 2 Turn the ignition off. Disconnect the ECM harness connector(s). NOTE: Check connectors - Clean/repair as necessary. Turn the ignition on. Measure the voltage of the Speed Control vent circuit between the Cruise Control Assembly harness connector and engine ground. Is the voltage above 1 volt? Yes --> Repair the Speed Control vent circuit for a short to voltage. No --> Go To 3 Turn the ignition off. Measure the resistance between the Speed Control Vacuum circuit and all other circuits in the ECM connectors. Is the resistance less than 10 ohms? Yes --> Repair the (V35) Speed Control vent circuit shorted to other circuit. No --> Go To 4 Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vent Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vent Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Go To 5 No --> Replace and program the ECM in accordance with the Service Information. Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Where any problems found? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). No --> Replace the Cruise control servo.

P0587 LOW VOLTAGE DETECTED AT THE SPEED CONTROL VENT DRIVER When Monitored and Set Condition: When Monitored: While driving and the Speed control is set. Set Condition: This code will set if the voltage detected on the Speed Control Vent circuit at the ECM is different than the expected voltage for 3 seconds. POSSIBLE CAUSES P0595 OR P0596 PRESENT SPEED CONTROL SERVO ASSEMBLY (V35) SPEED CONTROL VENT CIRCUIT OPEN (V35) SPEED CONTROL VENT CIRCUIT SHORTED TO GROUND (V35) SPEED CONTROL VENT CIRCUIT SHORTED TO OTHER CIRCUITS ECM INTERMITTENT CONDITION SPEED CONTROL SERVO DIAGNOSTIC PROCEDURE With the DRBIII®, read DTCs. Is the P0595 or P0596 set? Yes --> Repair the other DTCs first. No --> Go To 2 Turn the ignition off. Disconnect the Speed control servo harness connector. NOTE: Check connectors - Clean/repair as necessary. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vent Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vent Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Replace the speed control servo assembly. No --> Go To 3 Turn the ignition off. Disconnect the ECM harness connector(s). NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the Speed Control vent circuit between the Cruise Control Assembly harness connector and the ECM harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 4 No --> Repair the (V35) Speed Control vent circuit for an open. Measure the resistance between ground and the Speed Control vent circuit in the ECM harness connector. Is the resistance below 5.0 ohms? Yes --> Repair the (V35) Speed Control vent circuit for a short to ground. No --> Go To 5 Measure the resistance between the Speed Control Vacuum circuit and all other circuits in the ECM connectors. is the resistance less than 10 ohms? Yes --> Repair the (V35) Speed Control vent circuit shorted to other circuit. No --> Go To 6 Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vent Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vent Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Go To 7 No --> Replace and program the ECM in accordance with the Service Information. Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Where any problems found? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION. No --> Replace the Speed control servo.

P0584 HIGH VOLTAGE DETECTED AT THE SPEED CONTROL VACUUM DRIVER When Monitored and Set Condition: When Monitored: While the engine is running and the Speed control engaged. Set Condition: The Speed Control Vacuum commanded state is on and the feedback state is off. POSSIBLE CAUSES SPEED CONTROL SERVO ASSEMBLY (V36) SPEED CONTROL VACUUM CIRCUIT SHORTED TO VOLTAGE (V36) SPEED CONTROL VACUUM CIRCUIT SHORTED TO OTHER CIRCUITS ECM CRUISE CONTROL SERVO INTERMITTENT CONDITION DIAGNOSTIC PROCEDURE Turn the ignition off. Disconnect the Speed control servo harness connector. NOTE: Check connectors - Clean/repair as necessary. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vacuum Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vacuum Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Replace the speed control servo assembly. No --> Go To 2 Turn the ignition off. Disconnect the ECM harness connector(s). NOTE: Check connectors - Clean/repair as necessary. Measure the voltage of the Speed Control Vacuum circuit between the Speed Control Assembly harness connector and the ECM harness connector. Is the voltage above 1.0 volts? Yes --> Go To 3 No --> Repair the (V36) Speed control vacuum circuit shorted to voltage. Measure the resistance between the Speed Control Vacuum circuit and all other pins in the ECM connectors. Is the resistance less than 10 ohms? Yes --> Repair the (V36) Speed Control vacuum circuit shorted to other circuit. No --> Go To 4 Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vacuum Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vacuum Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Go To 5 No --> Replace and program the ECM in accordance with the Service Information. Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Where any problems found? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). No --> Replace the Cruise control servo.

P0583 LOW VOLTAGE DETECTED AT THE SPEED CONTROL VACUUM DRIVER When Monitored and Set Condition: When Monitored: With engine running and Speed control engaged. Set Condition: This code will set if the voltage detected on the Speed Control Vacuum circuit at the ECM is different than the expected voltage for 3 seconds. POSSIBLE CAUSES P0595 OR P0596 PRESENT (V36) SPEED CONTROL VACUUM CIRCUIT OPEN (V36) SPEED CONTROL VACUUM CIRCUIT SHORT TO GROUND ECM (V36) SHORTED TO OTHER CIRCUITS IN HARNESS INTERMITTENT CONDITION CRUISE CONTROL SERVO DIAGNOSTIC PROCEDURE With the DRBIII®, read DTCs. Is the P0595 or P0596 set? Yes --> Repair the other DTCs first. No --> Go To 2 Turn the ignition off. Disconnect the Speed Control Servo harness connector NOTE: Check connectors - Clean/repair as necessary. Turn the ignition on. With the DRBIII®, actuate the Speed control vacuum relay. Using a 12-volt test light connected to B+, check the Speed Control Vacuum solenoid Output circuit in the Speed Control Servo harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Test Complete. No --> Go To 3 Turn the ignition off. Disconnect the ECM harness connector(s). NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the Speed Control Vacuum circuit between the Cruise Control assembly harness connector and the ECM harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 4 No --> Repair the open (V36) Speed control vacuum circuit. Turn the ignition off. Measure the resistance between ground and the Cruise Control Vacuum circuit in the ECM harness connector. Is the resistance greater than 100k ohms? Yes --> Go To 5 No --> Repair the (V36) Speed Control Vacuum circuit for a short to ground. Measure the resistance between the Speed Control Vacuum circuit in the ECM harness connector and all other circuits in the ECM harness connectors. Is the resistance less than 10 ohms? Yes --> Go To 6 No --> Repair the shorted (V36) speed control vacuum solenoid circuit. Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vacuum Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vacuum Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Go To 7 No --> Replace and program the ECM in accordance with the Service Information. Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Where any problems found? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). No --> Replace the Cruise control servo.

P0583 LOW VOLTAGE DETECTED AT THE SPEED CONTROL VACUUM DRIVER When Monitored and Set Condition: When Monitored: With engine running and Speed control engaged. Set Condition: This code will set if the voltage detected on the Speed Control Vacuum circuit at the ECM is different than the expected voltage for 3 seconds. POSSIBLE CAUSES P0595 OR P0596 PRESENT (V36) SPEED CONTROL VACUUM CIRCUIT OPEN (V36) SPEED CONTROL VACUUM CIRCUIT SHORT TO GROUND ECM (V36) SHORTED TO OTHER CIRCUITS IN HARNESS INTERMITTENT CONDITION CRUISE CONTROL SERVO DIAGNOSTIC PROCEDURE With the DRBIII®, read DTCs. Is the P0595 or P0596 set? Yes --> Repair the other DTCs first. No --> Go To 2 Turn the ignition off. Disconnect the Speed Control Servo harness connector NOTE: Check connectors - Clean/repair as necessary. Turn the ignition on. With the DRBIII®, actuate the Speed control vacuum relay. Using a 12-volt test light connected to B+, check the Speed Control Vacuum solenoid Output circuit in the Speed Control Servo harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Test Complete. No --> Go To 3 Turn the ignition off. Disconnect the ECM harness connector(s). NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the Speed Control Vacuum circuit between the Cruise Control assembly harness connector and the ECM harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 4 No --> Repair the open (V36) Speed control vacuum circuit. Turn the ignition off. Measure the resistance between ground and the Cruise Control Vacuum circuit in the ECM harness connector. Is the resistance greater than 100k ohms? Yes --> Go To 5 No --> Repair the (V36) Speed Control Vacuum circuit for a short to ground. Measure the resistance between the Speed Control Vacuum circuit in the ECM harness connector and all other circuits in the ECM harness connectors. Is the resistance less than 10 ohms? Yes --> Go To 6 No --> Repair the shorted (V36) speed control vacuum solenoid circuit. Reconnect the ECM harness connectors. Ignition on, engine not running. With the DRBIII®, actuate the Speed Control Vacuum Solenoid. Using a 12-volt test light connected to battery positive, check the Speed Control Vacuum Solenoid Output circuit in the Speed Control Assembly harness connector. NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery. Does the test light cycle on and off and illuminate brightly? Yes --> Go To 7 No --> Replace and program the ECM in accordance with the Service Information. Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Where any problems found? Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). No --> Replace the Cruise control servo.

P0581 HIGH VOLTAGE DETECTED AT THE SPEED CONTROL SWITCH When Monitored and Set Condition: When Monitored: Key on or Engine running. Set Condition: Speed Control MUX switch above 11.5 volts for 5 seconds. POSSIBLE CAUSES S/C WIRING HARNESS OBSERVABLE PROBLEM CLOCKSPRING SIGNAL/GROUND CIRCUIT OPEN SPEED CONTROL ON/OFF SWITCH S/C SWITCH SIGNAL CKT SHORTED TO VOLTAGE S/C SWITCH SIGNAL CIRCUIT OPEN ECM TO CLOCK SPRING S/C SWITCH SIGNAL CIRCUIT OPEN CLOCKSPRING TO S/C SWITCH S/C SWITCH GROUND CIRCUIT OPEN CLOCKSPRING TO S/C SWITCH S/C SWITCH GROUND CIRCUIT OPEN ECM TO CLOCKSPRING ECM DIAGNOSTIC PROCEDURE Turn the ignition on. With the DRBIII® in Inputs/Outputs, read the Speed Control inputs state in ECM. While monitoring the DRBIII®, push the Speed Control On/Off Switch several times, then leave it on. Did the DRBIII® show Speed Control Switch off and on? Yes --> Go To 2 No --> Test Complete. Turn the ignition off. Using the Schematics as a guide, inspect the Wiring and Connectors. Were any problems found? Yes --> Repair as necessary. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 3 Disconnect the upper and lower 6-way clockspring harness connectors. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the sensor ground circuit between the upper and lower 6-way clockspring harness connectors. Measure the resistance of the speed control switch signal circuit between the upper and lower 6-way clockspring harness connectors. Was the resistance above 5.0 ohms for either circuit? Yes --> Replace the clockspring. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 4 Disconnect the Speed Control On/Off Switch 2-way harness connector only. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance across the S/C On/Off Switch. Is the resistance between 20.3K and 20.7K ohms? Yes --> Go To 5 No --> Replace the On/Off Switch. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). Turn the ignition on. Measure the voltage of the S/C Switch Signal Circuit at the On/Off Switch 2-way connector. Is the voltage above 6.0 volts? Yes --> Repair the Speed Control Switch Signal Circuit for a short to voltage. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 6 Turn the ignition off. Disconnect the ECM harness connector. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance of the S/C Switch Signal Circuit between the ECM connector and the Clockspring Connector. Is the resistance below 5.0 ohms? Yes --> Go To 7 No --> Repair open Speed Control Switch Signal Circuit ECM to Clock-spring. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). Measure the resistance of the S/C Switch Signal Circuit from the clockspring harness connector to the On/Off switch harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 8 No --> Repair the open Speed Control Switch Signal Circuit Clockspring to S/C switch. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). Measure the resistance of the S/C Switch Sensor Ground Circuit between the On/Off Switch 2-way harness connector to the clockspring harness connector. Is the resistance below 5.0 ohms? Yes --> Go To 9 No --> Repair open ground circuit from clockspring to S/C switch. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). Measure the resistance of the S/C Switch Sensor Ground Circuit between the ECM harness connector to the clockspring harness connector. Is the resistance below 5.0 ohms? Yes --> Replace and program the ECM in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Repair open ground circuit from ECM to clockspring. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL).

P0580 LOW VOLTAGE DETECTED AT THE SPEED CONTROL SWITCH When Monitored and Set Condition: When Monitored: While the ignition is on Set Condition: Speed control MUX switch below 1.0 volts for 5 seconds. POSSIBLE CAUSES S/C WIRING HARNESS OBSERVABLE PROBLEM S/C SWITCH (ON/OFF) CLOCKSPRING SHORTED TO GROUND S/C SWITCH (RESUME/ACCEL) S/C SWITCH SIGNAL CIRCUIT SHORTED TO GROUND S/C SIGNAL CIRCUIT SHORTED TO SENSOR GROUND ECM DIAGNOSTIC PROCEDURE Turn the ignition on. With the DRBIII®, read the S/C Switch volts status in the ECM. Is the S/C Switch voltage below 1.0 volt? Yes --> Go To 3 No --> Go To 2 Turn the ignition off. Using the Schematics as a guide, inspect the Wiring and Connectors. Were any problems found? Yes --> Repair as necessary. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 3 Turn the ignition off. Disconnect the S/C ON/OFF Switch harness connector. NOTE: Check connectors - Clean/repair as necessary. Turn the ignition on. With the DRBIII® in Sensors, read the S/C Switch volts in the ECM. Did the S/C Switch volts change to 5.0 volts? Yes --> Replace the S/C ON/OFF Switch. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 4 Turn the ignition off. Disconnect the S/C RESUME/ACCEL Switch harness connector. NOTE: Check connectors - Clean/repair as necessary. Ignition on, engine not running. With the DRBIII® in Sensors, read the S/C Switch volts in the ECM. Did the S/C Switch volts go above 4.0 volts? Yes --> Replace the Resume/Accel Switch. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 5 Turn the ignition off. Disconnect the clockspring 6-way harness connector (instrument panel wiring side). Turn the ignition on. With the DRBIII® in Sensors, read the S/C Switch volts in the ECM. Did the S/C Switch volts change to 5.0 volts? Yes --> Replace the Clockspring. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 6 Turn the ignition off. Disconnect the S/C ON/OFF Switch harness connector. Disconnect the ECM harness connectors. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance between the S/C Switch Signal circuit and ground (B-) at S/C ON/OFF Switch harness connector. Is the resistance below 5.0 ohms? Yes --> Repair S/C Switch Signal Circuit for a short to ground. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Go To 7 Measure the resistance between the S/C Signal Circuit and the Sensor Ground Circuit at the ON/OFF switch harness connector. Is the resistance below 5.0 ohms? Yes --> Repair S/C Signal Circuit shorted to Sensor Ground. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL). No --> Replace and program the ECM in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 4 (DIESEL).

P0573 HIGH VOLTAGE DETECTED AT THE BRAKE SWITCH When Monitored and Set Condition: When Monitored: While the ignition is on. Set Condition: POSSIBLE CAUSES BRAKE SWITCH SHORTED TO VOLTAGE DIAGNOSTIC PROCEDURE Repair Brake switch shorted to voltage.