Conditions for Setting the DTC

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

The system will test the motor circuits by checking for unwanted voltage.
The system supplies voltage on the Motor Control A circuit and reads the voltage back on the Motor Control B circuit.
The transfer case shift control module senses a low voltage return on the Motor Control A circuit or the Motor Control B circuit when a high voltage is expected.
If the system detects a problem with the circuits, the DTC is logged.