Test Description

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.

The numbers below refer to the step numbers on the diagnostic table.

2) - Tests the electrical function of the front axle actuator. Helps determine between mechanical and electrical malfunctions.
3) - Tests for proper power and ground at the front axle actuator.
4) - Tests the operation of the front axle control circuit.
5) - Helps determine if the transfer case shift control module is able to monitor the front axle switch.
6) - Tests the front axle switch circuit for an open or high resistance.
7) - Measures the voltage between the front axle feed circuit and ground.
8) - Tests the front axle control circuit for an open or high resistance.
9) - Inspects the front axle for a mechanical malfunction.
10) - Tests for open fuse in the front axle feed circuit.

Fig 1: Front Axle Will Not Engage Diagnosis (Steps 1-6)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Front Axle Will Not Engage Diagnosis (Steps 7-15)

Courtesy of GENERAL MOTORS CORP.