GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electric power steering (EPS) system uses a torque sensor to detect the amount of torque being applied to the steering column shaft when the steering wheel is turned. The power steering control module (PSCM) uses this sensor as the main input in determining the amount of steering assist needed.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0545 Steering Wheel Torque Input Sensor

Condition for Running the DTC

The ignition and the engine are ON.

Condition for Setting the DTC

    • The PSCM torque sensor input is greater than 17.2 N·m (12.6 lb ft) during a right turn.
    • The PSCM torque sensor input is less than -17.2 N·m (+12.6 lb ft) during a left turn.
    • The difference between the 2 torque sensor coils is greater than 2.4 N·m (1.7 lb ft).

Action Taken When the DTC Sets

    • A DTC C0545 is stored in memory.
    • The instrument panel cluster (IPC) displays the SERVICE VEHICLE SOON warning indicator.
    • No steering assist is provided.

Conditions for Clearing the DTC

    • A current DTC will clear on the next malfunction-free ignition cycle.
    • A history DTC will clear after 100 consecutive malfunction-free ignition cycles.
    • Using a scan tool

Diagnostic Aids

The torque sensor is hard wired to the PSCM, thus no connector or circuit testing can be performed. If an intermittent malfunction is suspected with the torque sensor or the circuits to the torque sensor, replace the EPS assembly. Refer to Steering Column Replacement . The scan tool can be used to view the torque sensor value.

Test Description

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

  1. This step tests the torque sensor in its active state.

Step

Action

Values

Yes

No

Schematic Reference: Power Steering Schematics

Connector End View Reference: Power Steering Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Start the engine.
  3. With the scan tool, observe the Torque Sensor Main data parameter in the EPS Data List 2.
  4. Turn the steering wheel 90 degrees to the right and hold the steering wheel position.

Does the scan tool indicate that the Torque Sensor Main data parameter changes state wile turning the steering wheel and is less than the specified value?

17.2 N·m  (12.6 lb ft)

Go to Diagnostic Aids

Go to Step 3

3

Replace the electric power steering (EPS) assembly. Refer to Steering Column Replacement .

Did you complete the repair?

--

Go to Step 4

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4

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

--

Go to Step 2

System OK