Diagnostic Aids

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Important: Perform the following in order to avoid misdiagnosis.

Inspect for proper operation of brake lamps and clutch switch, if equipped.
Inspect for proper operation of the transmission range switch.
EMI on the speed sensor signal circuit may cause erratic cruise control operation.
Wiring on upfitted equipment must also be tested.

Fig 1: Cruise Control Inoperative/Malfunctioning (Diesel) Diagnosis (Steps 1-10)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Cruise Control Inoperative/Malfunctioning (Diesel) Diagnosis (Steps 11-22)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Cruise Control Inoperative/Malfunctioning (Diesel) Diagnosis (Steps 23-35)

Courtesy of GENERAL MOTORS CORP.