Diagnostic Aids
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
To avoid a misdiagnosis, inspect for the following:
- Proper operation of the stop lamps. Refer to EXTERIOR LIGHTING SYSTEMS DESCRIPTION AND OPERATION .
- Proper operation of the clutch system, if equipped with a manual transmission. Refer to CLUTCH SYSTEM DESCRIPTION AND OPERATION .
- The throttle linkage is not binding.
EMI on the speed sensor signal circuit may cause erratic cruise control operation.