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 powerpack controller to provide the necessary pedal rate signal.

The BPP sensor is a resistive sensor with a total resistance between 3,000-5,000 ohms with a maximum current draw of less than 16 ma. The BPP sensor will output an analog signal that is referenced to 5 volts 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 degree range.

The EHPS provides the BPP sensor with 5 volts (actual 4.3 volts) on the 5-volt reference circuit and a ground on the low reference circuit. Rotation of the BPP sensor during brake pedal movement provides the EHPS with a signal voltage from 1-4 volts through the BPP sensor signal circuit. When the control module detects that the BPP sensor signal or 5-volt reference voltage is outside the predetermined range, DTC C0870 is set.