GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The instrument panel cluster (IPC) illuminates the Service 4-Wheel Steer indicator. The rear wheel steering control module sends a Class 2 serial data message to the IPC in order to command the indicator ON or OFF.

Diagnostic Aids

Check all connections between the IPC and the rear wheel steering control module for loose or damaged terminals or damaged wiring .Use of the Diagnostic System Check will help ensure that there are not other conditions or DTC's that will cause a loss of communication between modules.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests if the IPC is able to illuminate the Service 4-Wheel Steer indicator during the bulb check.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check-Rear Wheel Steering?

Go to Step 2

Go to Diagnostic System Check - Rear Wheel Steering

2

  1. Turn the ignition switch to the OFF position for 5 seconds.
  2. Turn the ignition switch to the ON position while observing the Service 4-Wheel Steer indicator

Does the Service 4-Wheel Steer indicator illuminate for 2 seconds and then turn OFF?

Go to Diagnostic Aids

Go to Step 3

3

  1. Install a scan tool.
  2. Select the rear wheel steering special function menu on the scan tool.
  3. Command the Service 4-Wheel Steer lamp ON.

Does the Service 4-Wheel Steer indicator turn ON?

Go to Step 5

Go to Step 4

4

Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 6

5

Important: Perform the Learn Alignment procedure. Refer to in Wheel Alignment. Wheel Alignment Measurement

Replace the rear wheel steering module. Refer to . Rear Wheel Steering Control Module Replacement

Did you complete the replacement?

Go to Step 6

--

6

  1. Turn the ignition switch to the OFF position for 5 seconds.
  2. Turn the ignition switch to the ON position while observing the Service 4-Wheel Steer indicator.

Does the Service 4-Wheel Steer indicator illuminate for 2 seconds and then turn OFF?

System OK

Go to Step 3