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 ReceivedCircuit/System Description
The PSCM monitors vehicle speed validity message from the engine control module (ECM) via the GMLAN serial data circuit. The power steering control module (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
Connector End View Reference
Power Steering Connector End Views
Description and Operation
Power Steering System Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Verify there are no speed sensor related DTCs set in the ECM.
| ⇒ | If any speed sensor related DTCs are set in the ECM, diagnose those DTCs first. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
