FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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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-C3:






C3-C5:






C5-C7:






C7-C8:






C9-C10:






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

Possible Causes
- Circuit 151 (LB/BK) open, short to voltage or ground
- Circuit 848 (DG/OG) open or short to voltage
- Clockspring
- Speed control switch
- PCM