Circuit/System Description
WARNING: This page is about a different car, the 2011 GMC Cab & Chassis Sierra, 2011 Chevrolet Suburban, and 2011 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The electronic brake control module (EBCM) supplies a 5 V reference and provides a low reference to the steering wheel angle sensor. The EBCM monitors the signal circuit and the three phase circuits to determine the steering wheel position. The EBCM receives three signal inputs from the steering angle sensor. The Index Pulse signal is only High when the steering wheel is centered or within a few degrees of the straight ahead position. The 2 input signals Phase A and Phase B are approximately 90 degrees out of phase. Once calibrated, the EBCM dynamically interprets the relationship between the Phase A and Phase B inputs, and determines the position of the steering wheel and the direction of the steering wheel rotation.