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Home >> Ford >> 2007 >> Expedition 4WD V8-5.4L >> Repair and Diagnosis >> Cruise Control >> Testing and Inspection >> Pinpoint Tests >> Test C: DTC P0579 or DTC P0581 - Speed Control Switch Circuit Failure
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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-C2:






C2-C4:






C4-C6:






C6-C8:






C8-C10:






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

DTC P0579 - may set when the speed control switch circuits are open, shorted to voltage or shorted to ground.

DTC P0581 - sets when the speed control switch circuits are open or shorted to voltage.

Possible Causes
- Circuit RES08 (GN/BN) open, short to voltage or ground
- Circuit VES10 (WH) open, short to voltage or ground
- Clockspring
- Speed control switch
- PCM
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