Normal Operation
The normally-closed Brake Pedal Position (BPP) switch (also known as the speed control deactivation switch) receives fused battery voltage from Bussed Electrical Center (BEC) fuse 47 (15A) along circuit 391 (RD/YE) when the ignition key is turned to the RUN position. This voltage is sent through the BPP switch to the ABS module and the PCM along circuit 535 (LB/RD). When the brake pedal is applied, the BPP opens and the voltage signal is no longer referenced by the ABS module and PCM.
When the fluid level in the brake master cylinder reservoir reaches a predetermined level, the brake fluid level switch closes and voltage is sent to the Smart Junction Box (SJB). The SJB then sends a message to the ABS module along the High Speed Controller Area Network (HS-CAN) bus network.
- DTC C1446 Brake Switch Circuit Failure - If during normal operation the ABS module determines that the BPP information is invalid when compared to other inputs (brake pressure transducer and wheel speed sensors) or if the brake pedal message is missing completely, DTC C1446 will be set. Also, a low brake fluid level in the master cylinder reservoir or an open, short to ground or short to voltage in the brake fluid level switch that the SJB interprets as a low fluid condition will cause DTC C1446 to be set.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- BPP switch
- ABS module