Conditions for Setting the DTC

WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The system will try to engage the front axle. If it can not engage the front axle, the system will not attempt it again during that ignition cycle.
The transfer case shift control module reads back the front axle output as a high voltage when a low voltage is expected.