Normal Operation
WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
When the brake pedal is applied, the normally open stoplamp switch closes and sends a voltage to the PCM disengaging the cruise control.
The normally closed cruise control deactivator switch (part of the stoplamp switch), opens and removes the voltage signal to the PCM when the brake pedal is applied firmly. This is a redundant cruise control deactivation signal to the PCM.
- DTC P0572 (Brake Switch A Circuit Low) - sets when the PCM senses a short to ground in the stoplamp switch circuits.
- DTC P0573 (Brake Switch A Circuit High) - sets when the PCM senses a open or a short to voltage in the stoplamp switch circuits.
- DTC P1703 (Brake Switch Out Of Self Test Range) - sets when there is an open or short in the deactivator switch circuits or when there is an open or short in the stoplamp circuits when the PCM self test is carried out.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Cruise control deactivator switch (integral to the stoplamp switch)
- ABS module
- PCM