Brake (Stop Lamp) Switch Sense Circuit

Name of Code:
Brake (Stop Lamp) Switch Sense Circuit

When Monitored:
With engine running.

Set Condition:
Decel (30 - 0 mph). The PCM monitors the brake switch signal expecting it to be continuously low while the vehicle speed cycles 16 times. The count is reset to zero whenever the brake switch indicates a high signal. Accel (0 - 20 mph): The PCM monitors the brake switch signal expecting it to be high while the following maneuver occurs 16 times. After the vehicle speed increases, the PCM must accumulate 6 seconds while delta throttle voltage is above 0.02 volts. The count is reset to zero whenever the brake switch indicates a low signal.

Theory of Operation:
The brake switch signal is used to disable speed control by venting the Speed Control (S/C) servo. The brake switch signal is used to disable (3 speed ATX) the part throttle unlock, as well as disabling the vehicle speed sensor diagnostics. The signal from the brake switch is used to enable OBDII purge monitor. It also modifies the stall torque management control.

Possible Causes:
- Brake switch failure
- Switch alignment
- Connector terminals
- Connector wires