Conditions for Setting the DTC

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The system will try to turn the lock solenoid off by opening the ground circuit.
If the module is unable to de-energize the solenoid, the system will not attempt to de-energize the solenoid again during that ignition cycle.
Transfer Case Lock output reads back as a low voltage when a high voltage is expected.