Normal Operation
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The stoplamp switch is a single plunger 2-stage switch with 2 inputs to the PCM. When the brake pedal is applied, the first stage, which is a normally open stoplamp switch, closes and sends a voltage signal to the PCM deactivating the cruise control, if engaged. The second stage is the normally closed cruise control deactivator switch (integral to the stoplamp switch), which opens and removes the ground signal to the PCM when the brake pedal is firmly applied. This is a redundant signal to the PCM. There is less than one millimeter in plunger travel between the first and second stage.
| DTC Description | Fault Trigger Conditions |
|---|---|
| P0504 - Brake Switch A/B Correlation | A DTC that sets when the PCM does not sense the correct sequence of the brake pedal input signal from both the cruise control deactivator and stoplamp switches when the brake pedal is pressed and released. |
| P0572 - Brake Switch A Circuit Low | A DTC that sets when the PCM detects an open in the stoplamp switch signal. The PCM monitors the vehicle speed, the engine speed, the engine torque and the stoplamp BOO input during start and stop driving cycles. If the BOO input to the PCM is always off during start and stop driving cycles this DTC sets in continuous memory. |
| P0573 - Brake Switch A Circuit High | A DTC that sets when the PCM detects an short to voltage on the stoplamp switch signal. The PCM monitors the vehicle speed, the engine speed, the engine torque and the stoplamp BOO input during start and stop driving cycles. If the BOO input to the PCM is always on during start and stop driving cycles this DTC sets in continuous memory. |
| P1703 - Brake Switch Out Of Self-Test Range | A DTC that sets in the PCM during the self-test, when the brake switch input signal is high or does not cycle high and low. |
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Stoplamp switch
- Cruise control deactivator switch (integral to the stoplamp switch)
- PCM
- ABS module