Test C: Power Mode Mismatch: Description
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Normal vehicle Class 2 communications and module operations will not begin until system power mode has been identified. Discrete wires from ignition switch contacts are monitored by Dash Integration Module (DIM) to determine correct power mode. DIM communicates system power mode to all Class 2 modules on Class 2 serial data line.