Diagnostic Aids

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 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 brake lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems.
Proper operation of the clutch system, if equipped with a manual transmission. Refer to Clutch System Description and Operation in Clutch.
The throttle linkage is not binding.

EMI on the vehicle speed sensor signal circuit may cause erratic cruise control operation.