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 151 (LB/BK) to the speed control switches, which passes through the clockspring. The signal return is provided through circuit 848 (DG/OG) and the clockspring.
- DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - may set when the speed control switch circuits are open, shorted to voltage or shorted to ground.
- DTC P0581 (Cruise Control Multifunction Input A 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-C2:

C2-C4:

C4-C6:

C6-C7:

C8-C10:

C10-C11: