Circuit Description

WARNING: This page is about a different car, the 2004 GMC Yukon XL and 2004 GMC Yukon. However, it is still accessible from the selected car via links, so may be relevant.

The transfer case shift control module consists of four encoder channels, which are supplied 5 volts. These four channels are P, C, A, and B, each running to a switch located inside the encoder/motor assembly. When a particular encoder channel is active, the switch is closed and 5 volts flow through the encoder signal return circuit. If the module wants to request motor position, a low side driver pulls the voltage low on the encoder signal return and the corresponding channel circuit, indicating motor position.

The transfer case shift control module supplies 5 volts on all the channels. As these channels are pulled to ground, the module can interpret the location of the transfer case shift position.

This DTC detects an open, high resistance or a short to voltage in the encoder signal return circuit, or an open, high resistance or short to voltage in the encoder channel circuits.