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 Descriptors

DTC P0500: Vehicle Speed Signal Range/Performance

### Circuit/System Description

The ECM uses the ABS wheel speed signal to calculate the vehicle speed. The ABS module transmitts the wheel speed signal to the ECM via the serial data circuit. The ECM calculates and sends the vehicle speed data to the steering column control module (SCCM) which in turn sends the vehicle speed information to the IPC via the serial data circuit for display in the speedometer.

### Conditions for Running the DTC

• | The engine is running.

• | The ignition voltage is between 9-18 volts.

### Conditions for Setting the DTC

• | The ECM detects that the vehicle speed information is invalid.

• | The above condition must be present for a minimum of 8 seconds.

### Action Taken When the DTC Sets

The ECM records the operating conditions at the time the diagnostic fails. The ECM displays the failure information in the Failure Records on the scan tool.

### Conditions for Clearing the DTC

• | The DTC becomes history when the conditions for setting the DTC are no longer present.

• | The history DTC clears after 40 malfunction-free warm-up cycles.

### Reference Information

#### Schematic Reference

Instrument Cluster Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Instrument Cluster 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

Important: The drive wheels of the vehicle must be raised and the transmission must be placed in drive or first gear. Refer to Lifting and Jacking the Vehicle.

1. Ignition ON and the scan tool installed, verify there are no vehicle wheel speed sensor DTCs set in the ABS module.

⇒ | If any wheel speed sensor DTCs are present, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

2. Ignition ON and the scan tool installed, perform the IPC Vehicle Speed Control Test from the ECU Control menu. Verify that the speedometer pointer moves from the minimum value to the maximum value as commanded.

⇒ | If the speeometer does not perform the Vehicle Speed Control Test, replace the IPC.

3. With the drive wheels raised start the engine and place the vehicle transmission in drive or the first gear. Verify that the speedometer value matches the scan tool Vehicle Speed parameter in the ECM Engine Data List.

⇒ | If the speedometer is incorrect, test or replace the IPC.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for the IPC replacement, setup and programming.