DTC P1597: Speed Control Switch Always Low
NOTE:
For connector terminal ID, see CONNECTOR IDENTIFICATION
. For wiring diagram, see
WIRING DIAGRAMS article.
NOTE:
Monitored with ignition on and battery voltage more than 10.4 volts. Set condition is when switch voltage is less than 4.5 volts for 2 minutes. Possible causes are: speed control switch signal circuit shorted to ground, speed control signal circuit shorted to sensor ground, PCM defective or speed control switch defective.
- Turn ignition on with engine off. Using scan tool, record all DTCs and freeze frame data. Erase DTCs. Using scan tool, read speed control switch volts in SENSORS. If speed control switch voltage is less than one volt, go to next step. If speed control switch voltage is one volt or more, test is complete.
- Turn ignition off. Disconnect speed control switch 2-pin connector. Using a DVOM, check resistance between speed control switch signal circuit (Pink/Light Green wire) and PCM connector C2 connector terminal No. 43 (Black/Light Blue wire). Powertrain Control Module (PCM) connector C2 (located nearest to rear of vehicle). PCM is located to left of Power Distribution Center (PDC) in engine compartment. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair speed control signal circuit short to sensor ground. Perform TEST VER-4A: SPEED CONTROL VERIFICATION .
- Turn ignition on with engine off. Using scan tool, read speed control switch volts in SENSORS. If speed control switch volts did not change to 5 volts, go to next step. If speed control switch volts changed to 5 volts, replace speed control switch. Perform TEST VER-4A: SPEED CONTROL VERIFICATION .
- If no other potential causes are remaining, PCM is assumed to be defective. Replace PCM. Perform TEST VER-4A: SPEED CONTROL VERIFICATION .