Conditions for Setting the DTC

WARNING: This page is about a different car, the 2009 GMC Yukon, 2009 Chevrolet Tahoe, 2009 Chevrolet Suburban, and 2009 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The transfer case control module sees a incremental 8-volt reference signal that is not between 1.5-8.2 volts indicating a short to ground or open if low and a short to voltage if high.
The module does not receive a incremental impulse signal voltage between 0.5-4.6 volts.
The incremental low reference circuit has an open or high resistance.