Conditions for Setting the DTC

WARNING: This page is about a different car, the 2004 Oldsmobile Bravada and 2004 Buick Rainier. However, it is still accessible from the selected car via links, so may be relevant.

The system tests the motor circuits by checking for unwanted voltage.
Then, the system supplies voltage on each of the motor circuits and reads the voltage back on the other circuit.
If the system detects a condition with the circuits, the DTC is logged. The transfer case shift control module senses a low voltage return in the motor feed A or motor control B circuits when a high voltage is expected.
The fault must remain current for 30 seconds to set the DTC.
The transfer case shift control module provides a reference voltage of 4.5 volts on the motor A/B line for diagnostic purposes.