Diagnostic Aids

WARNING: This page is about a different car, the 2014 GMC Yukon XL 1500, 2014 GMC Yukon, 2014 Chevrolet Tahoe, and 2014 Chevrolet Suburban 1500. However, it is still accessible from the selected car via links, so may be relevant.

The transfer case drain plug provides a good ground point.
The EL-49742 harness provides a good source for 12 V and ground.
Inspect the rear internal gear teeth for damage.
Visually inspect the VSS for cracks or damage.
Ensure the VSS is properly torqued to the transfer case housing.
This diagnostic relates to the VSS located in the transfer case and not the OSS located within the transmission.