Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Sierra and 2008 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The transfer case control module commands shifts through motor A and motor B control circuits causing the transfer actuator to shift the transfer case to different modes or ranges depending on driver selection. If the shift lever detent shaft were to bind, or there was a mechanical failure, or motor A control and motor B control were shorted together the shift would not be completed. This will cause the DTC to set in order to protect system components from damage.