Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

During diagnosis, park the vehicle on a level surface.
Inspect the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface.
Find out from the customer the conditions under which the DTC was set. This information will help to duplicate the failure.
The snapshot function on the scan tool can help find an intermittent DTC.