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 wheel speed sensor receives 12 V reference from the electronic brake control module (EBCM) and provides a DC square wave signal back to the module. As the wheel spins, the EBCM uses the frequency of the square wave signal to calculate the wheel speed.