GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The power steering control module (PSCM) monitors the temperature of the electric power steering (EPS) system. The PSCM uses voltage and current levels to calculate an estimated system temperature. If the PSCM detects a high system temperature event is occurring, the amount of assist is reduced to lower the EPS system temperature to prevent system thermal damage.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0476 Electric Steering Motor Circuit Range/Performance

Condition for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The PSCM detects a high system temperature.

Action Taken When the DTC Sets

    • A DTC C0476 is stored in memory.
    • Steering assist is reduced.

Conditions for Clearing the DTC

    • A current DTC will clear when the EPS system temperature returns to normal.
    • A history DTC will clear after 100 consecutive malfunction-free ignition cycles.
    • Using a scan tool

Diagnostic Aids

    • DTC C0476 does not indicate that a malfunction has occurred. Rather that the PSCM had to limit current to the EPS motor to avoid system thermal damage.
    • Inspect the under dash area around the EPS assembly. Ensure that no other components have come in contact with the EPS assembly such as under dash insulation or other electrical components.
    • Ensure that no steering components down stream of the EPS assembly, such as ball joints, tie rod ends, universal joints, or the steering rack and pinion are mechanically binding.

Test Description

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

  1. This step tests if the high system temperature is system, or driving condition related.

Step

Action

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?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Since most occurrences of the DTC are caused by frequent static steering, such as parking maneuvers and high ambient temperatures, review the electric power steering (EPS) system with the customer to determine the conditions under which the DTC set.

Did steering conditions or high ambient temperatures cause the DTC to set?

Go to Step 3

Go to Diagnostic Aids

3

  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