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Home >> Ford >> 2008 >> Focus L4-2.0L >> 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

Normal Operation
The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The signal is grounded by the PCM through circuit RES08 (GN/BN) and the clockspring.
- DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - may set when a speed control switch is stuck or the switch circuits are open, shorted to voltage or shorted to ground.
- DTC P0581 (Cruise Control Multifunction Circuit High) - 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


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