Normal Operation
WARNING: This page is about a different car, the 2009 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
The PCM sends a signal through circuit 248 (TN/OG) to the speed control switches. The return signal is sent through circuit 133 (BK). Both circuits pass through the clockspring.
- DTC P0579 (Speed Control Switch Circuit Failure) - sets when the speed control switch circuits are open, shorted to voltage or shorted to ground.
- DTC P0581 (Speed Control Switch Circuit Failure) - 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