Circuit Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The brake pedal position (BPP) sensor provides an analog pedal position signal. Its output is hardwired to the electro-hydraulic power steering (EHPS) connector. The signal must be digitized and differentiated within the EHPS module to provide the necessary pedal rate signal.

The BPP sensor is a resistive sensor with a total resistance between 3 k-5 k ohms with a maximum current draw of less than 16 ma. The BPP sensor will output an analog signal that is referenced to 5 volt which may increase or decrease monotonically with brake pedal depression. The sensor analog output shall have a specified electrical output over a mechanical range of 32 degrees rotation of the brake pedal pivot. Out-of-range values will be provided outside of the 32 degrees range.

The powertrain control module (PCM) reads the zero adjust brake switch (ZABS) state as depressed or not depressed and reports this information to the EHPS on the GMLAN bus. When the BPP sensor signal voltage is equal to a value that represents the brake pedal is at rest, the PCM should provide a serial data message reporting that the ZABS is not depressed. When the BPP sensor signal voltage is equal to a value that represents the brake pedal has been depressed, the PCM should provide a serial data message reporting that the ZABS is depressed. When the control module detects that the BPP sensor signal does not correlate with the ZABS information, DTC C0294 is set.