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 C0561 71: System Disabled Information Stored Invalid Serial Data Received

Circuit/System Description

The power steering control module (PSCM) monitors vehicle speed validity message from the engine control module (ECM) via the serial data circuit. The PSCM uses this vehicle speed message, along with the torque sensor and motor rotational sensor inputs, to determine the desired amount of steering assist.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The PSCM receives an invalid, or no vehicle speed message from the ECM.

Actions Taken When DTC Sets

    • DTC C0561 71 is stored in memory.
    • The driver information center (DIC) displays the SERVICE POWER STEERING warning message.
    • Steering assist level defaults to 120 km/h (74.5 mph) vehicle speed level of assist.

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.

Reference Information

Schematic Reference

Power Steering Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Steering System 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 there are no speed sensor related DTCs set in the ECM.

If any speed sensor related DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.