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Home >> Lincoln >> 2006 >> LS V8-3.9L VIN A >> 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-C9:






Normal Operation
The powertrain control module (PCM) sends a signal through circuit 7-PG24 (YE/BU) to the speed control switch, which passes through the clockspring. The return signal is sent through circuit 31S-PG24 (BK/OG)/31S-PG1 (BK/BU) and the clockspring.

Possible Causes
- Circuit 7-PG24 (YE/BU) open, short to voltage, or short to ground
- Circuit 31S-PG1 (BK/BU) open, short to voltage, or short to ground
- Circuit 31S-PG24 (BK/OG) open, short to voltage, or short to ground
- Clockspring
- PCM
- Speed control switch
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