Conditions for Setting the DTC
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
There is a difference of at least 75 percent between the ignition 1 voltage circuit and the instrument panel cluster (IPC) battery positive voltage circuit for 3 seconds.