Diagnostic Aids
WARNING: This page is about a different car, the 2011 GMC Yukon, 2011 Chevrolet Tahoe, and 2011 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
Many controllers such as the drive motor generator power inverter module, transmission control module (TCM), and inflatable restraint sensing and diagnostic module will set a DTC for a problem with the RUN, ON, and START power voltage circuits. Confirm that they do not have DTCs before only investigating the serial data gateway module.