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

C1-C2:

C2-C4:

C4-C6:

C6-C8:

C9-C11:

Normal Operation
The powertrain control module (PCM) sends a signal through circuit 151 (LB/BK) to the speed control switches which passes through the clockspring. The return signal is sent through circuit 848 (DG/OG) and the clockspring.

Possible Causes
- circuit 151 (LB/BK) open, short to voltage, or short to ground
- circuit 848 (DG/OG) open short to voltage
- clockspring
- speed control switch
- horn switch wiring harness
- PCM