Circuit/System Description
WARNING: This page is about a different car, the 2010 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The power steering control module (PSCM) continuously monitors the position of the power steering motor, the voltage and current levels commanded to it. It uses the motor position data to determine if a loss of mechanical coupling has occurred between the motor and the steering column shaft. The PSCM also compares the commanded and feedback current levels to detect malfunctions in the power steering motor.