For 1990-2009 cars

### 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 provides an overview of each diagnostic category.

### DTC Descriptor

DTC C0000 71: Vehicle Speed Information Circuit

### Circuit/System Description

The power steering control module (PSCM) receives a vehicle speed message from the engine control module (ECM) via the serial data circuit. The PSCM uses this vehicle speed message, and other inputs, to determine the desired amount of steering assist. At lower speeds, more assist is provided for easy turning during parking maneuvers. At higher speeds, less assist is provided for improved road feel and directional stability.

### Conditions for Running the DTC

• | The ignition is ON.

• | DTC U2100, U2105, 2107, or U2109 is not set.

• | Power steering system voltage is between 9-16 volts.

### Conditions for Setting the DTC

The PSCM receives an invalid vehicle speed message from the ECM.

### Action Taken When the DTC Sets

• | DTC C0000 71 is stored in memory.

• | The DIC displays the POWER STEERING warning message.

• | Steering assist is set to a default level.

### Conditions for Clearing the DTC

• | A current DTC will clear when the malfunction is no longer present.

• | A history DTC will clear after 100 consecutive malfunction-free ignition cycles.

### Diagnostic Aids

This DTC is for information only. As an aid to the technician, this DTC indicates that their are no problems in the PSCM. The ECM should be checked for a possible fault.

### 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

1. Verify that no DTCs are set in the ECM.

⇒ | If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.