GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptor

DTC C056E 4B: ECU Software Performance Calibration Not Learned

Circuit/System Description

The power steering control module (PSCM) monitors the learned or unlearned status of the steering angle sensor. The steering angle sensor must be learned or the power steering control module will not function.

Conditions for Running the DTC

The ignition is ON. Engine running.

Conditions for Setting the DTC

The steering angle sensor neutral position has not been learned.

Action Taken When the DTC Sets

    • Active Steering is disabled.
    • SERVICE STEERING SYS and/or STABILITY SECURE MODE is displayed on the DIC.

Conditions for Clearing the DTC

A current DTC will clear when a valid steering actuator neutral position has been learned.

Reference Information

Schematic Reference

Power Steering Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Active Front Steering Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Verify DTC C056E 4B is not set.

If the DTC is set, perform the scan tool PSCM Calibration Procedure. Refer to Power Steering Control Module Programming and Setup.