GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 ION 🢒 Suspension 🢒 Suspension General Diagnosis 🢒 Diagnostic System Check - Power Steering System

Test Description

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

  1. The lack of communication may be caused by a partial or a total malfunction of the circuit containing the class 2 serial data. The specified procedure will determine the particular condition.

    2.

  2. The presence of DTCs which begin with a U indicate some other module is not communicating. The specified procedure will collect all the available information before tests are performed.

    3.

  3. The Body Control Module (BCM) contains the Electric Power Steering (EPS) calibration. The presence of a DTC which begins with a B indicates the EPS system could be disabled due to a BCM malfunction.

    4.

  4. Tests if a malfunction exists in the EPS system.

    5.

  5. Tests if the steering column shaft is bent, twisted or damaged due to a previous collision and or air bag deployment.

Step

Action

Value(s)

Yes

No

1

Install a scan tool.

Does the scan tool turn on?

--

Go to Step 2

Go to Scan Tool Does Not Power Up in Data Link Communications

2

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the Power Steering Control Module (PSCM).

Does the scan tool communicate with the PSCM?

--

Go to Step 3

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

3

Select the Diagnostic Trouble Codes (DTC) function on the scan tool.

Does the scan tool display any DTCs that begin with a U?

--

Go to Diagnostic Trouble Code (DTC) List in Data Link Communications

Go to Step 4

4

Does the scan tool display DTC C0550, or any DTCs that begin with a B?

--

Go to Diagnostic Trouble Code (DTC) List in Body Control Systems

Go to Step 5

5

Does the scan tool display any EPS DTCs?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 6

6

  1. Start the engine.
  2. Turn the steering wheel 90° to the left, then 90° to the right, then return the steering wheel to center.
  3. remove hands from steering wheel and ensure no force is being applied to the steering wheel.
  4. Using the scan tool observe the Steering Shaft Torque data parameter in the EPS data list 2.

Does the scan tool indicate that the Steering Shaft Torque data parameter is within the specified range?

< + or - 1 N·m(0.7 lb ft)

Go to Symptoms - Power Steering System

Go to Steering Column Replacement in Steering Wheel and Column