Circuit/System Description
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The power steering control module (PSCM) compares the VIN stored in EEPROM with the VIN provided via the serial data circuit by the body control module (BCM). If the PSCM is replaced, the VIN needs to be copied from the existing PSCM over to the new PSCM using the SPS EPS Setup Procedure.