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 .