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Home >> Mercury >> 2007 >> Milan FWD L4-2.3L VIN Z >> 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-C3:






C3-C5:






C5-C6:






C7-C9:






C9-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 shorted to voltage or open.

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