Circuit/System Description
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) contains the 2-amp EPS fuse. When the ignition is ON the BCM supplies voltage to the ignition circuit to wake up the power steering control module (PSCM). The PSCM receives a serial data message from the BCM to determine the position of the ignition switch. When a power mode message is received, the PSCM monitors the ignition voltage circuit to detect if a short to voltage, short to ground, or an open exists.