Diagnostic Aids
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
Repair any brake system related symptoms and DTCs before performing this diagnostic.
In order to avoid misdiagnosis, inspect for the following:
- Ensure that the following cruise control switches are not stuck in the engaged position:
- On/Off switch
- - SET switch
- + RES switch
- Cancel switch
- Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan tool, observe the Cruise On/Off Switch, Cruise Resume/Accel Switch, Cruise Set/Coast Switch and Cruise Cancel Switch parameters in the ECM Cruise Control data list. This will help eliminate the possibility of an internally shorted inflatable restraint steering wheel module coil.
- Inspect for proper operation of the stop lamps and the braking system. Refer to Exterior Lighting Systems Description and Operation .
- Electromagnetic interference (EMI) on the speed sensor signal circuit may cause erratic cruise control operation.