Normal Operation
WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The PCM sends a signal through circuit VES10 (WH) to the speed control switches, which passes through the clockspring. The return signal is sent through circuit RES08 (GN/BN) and the clockspring.
DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - may set when the speed control 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:
- Fuse
- Wiring, terminals or connectors
- PCM not configured for speed control
- Clockspring
- PCM
- Speed control switch