Circuit/System Description

WARNING: This page is about a different car, the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The transfer case encoder motor (TCEM) is a bi-directional, permanent magnet, DC motor. When energized, through motor control A or motor control B, the ground is provided by the opposing motor control circuit and then grounded through the transfer case shift control module (TCCM) ground circuit, the TCEM, through a series of gears, rotates the transfer case control actuator shaft which moves the transfer case two/four wheel drive actuator cam and transfer case high/low shift fork to shift the transfer case between the following modes or ranges:

2WD HI
4WD Auto
4WD HI

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.