Circuit Description
WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The EBCM learns the model that it is installed in by using the Vehicle ID information (VIN) via the class 2 serial data line. Each time the vehicle is in the RUN position or the PCM communicates this information via Class 2, the EBCM internally compares the VIN information with that information stored in digits 2 through 5 of the VIN. If digit 5 of the VIN is incorrect, the EBCM will indicate a VIN information error is present.