Visual/Physical Inspection

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2015 GMC Sierra 3500 HD, 2015 GMC Sierra 2500 HD, 2015 GMC Sierra 1500, 2015 Chevrolet Silverado 3500 HD, and 2015 Chevrolet Silverado 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

Inspect for aftermarket devices which may affect the operation of the system. Refer to Checking Aftermarket Accessories .
Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
Make sure the parking assist sensors located on the vehicle front and rear bumper are clear. Remove any snow, mud or ice that is blocking the sensors.