Test C: DTC P0579 Or DTC P0581 - Speed Control Switch Circuit Failure

PINPOINT TEST C: DTC P0579 OR DTC P0581 - SPEED CONTROL SWITCH CIRCUIT FAILURE

Normal Operation
The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The signal is grounded by the PCM through circuit RES08 (GN/BN) and the clockspring.
- DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - may set when a speed control switch is stuck or the switch circuits are open, shorted to voltage or shorted to ground.
- DTC P0581 (Cruise Control Multifunction Circuit High) - sets when the speed control switch circuits are shorted to voltage or open.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Clockspring
- Speed control switch
- PCM

C1-C3:

C3-C5:

C5-C7:

C7-C9:

C9-C10:

C10-C11: