Circuit/System Description
WARNING: This page is about a different car, the 2008 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The steering wheel position sensor supplies 2 analog inputs, Phase A and Phase B, to the electronic brake control module (EBCM). The 2 input signals are approximately 90 degrees out of phase. By interpreting the relationship between the 2 inputs, the EBCM can determine the position of the steering wheel and the direction of the steering wheel rotation.