GM Service Manual Online
For 1990-2009 cars only

System Familiarization

Review the electric power steering (EPS) system operation in order to familiarize yourself with the correct system functions and operations. Refer to Power Steering System Description and Operation .

Visual/Physical Inspection

    • Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Inspect for aftermarket components such as tires, or wheels which could affect the operation and/or performance of the power steering system.
    • Inspect the steering column for accident damage. Refer to Steering Column Accident Damage Inspection in Steering Wheel and Column.

System Diagnosis

After incorrect system operation has been verified and that aftermarket devices, or intermittent conditions are not the cause, begin the system diagnosis with the Vehicle Diagnostic System Check. The Vehicle Diagnostic System Check will provide the following information:

  1. The identification of the control modules that control the Power Steering System.
  2. The ability of those control modules to communicate via the serial data circuit.
  3. The presence of any stored diagnostic trouble codes (DTCs) in those control modules and there status.

The use of the Vehicle Diagnostic System Check will identify the correct procedure for diagnosing the malfunction and where the procedure is located. Refer to Diagnostic System Check - Vehicle .