Normal Operation

The PCM sends a signal through circuit VES10 (WH) to the speed control switches which passes through the clockspring. The return signal is sent through circuit RES08 (GN/BN) and the clockspring.

• DTC P0579 (Speed Control Switch Circuit Failure) - may set when the speed control switch circuits are open, shorted to voltage or ground.
• DTC P0581 (Speed Control Switch Circuit Failure) - sets when the speed control switch circuits are open or shorted to voltage.

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• Clockspring
• Speed control switch
• PCM