Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Perform the following in order to avoid a misdiagnosis:

Inspect for proper operation of the brake lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems.
EMI on the vehicle speed sensor signal circuit may cause erratic cruise control operation.

For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.