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

### Circuit/System Description

The instrument panel cluster (IPC) displays the vehicle speed based on the vehicle speed information from the engine control module (ECM). The ECM sends the vehicle speed information via the serial data circuit to the body control module (BCM). The BCM then sends the information via the serial data circuit to the IPC in order to display the vehicle speed and accumulated miles traveled.

### 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

1. Ignition ON, perform the speedometer sweep test with the scan tool. Verify that the speedometer sweeps from its low to high position.

⇒ | If the speedometer gage does not sweep from its low to high position, replace the IPC.

2. Ignition OFF, raise the vehicles drive wheels.
3. Engine ON, transmission in drive or 1st gear, verify the scan tool Vehicle Speed Sensor parameter matches the speedometer display.

⇒ | If the Vehicle Speed Sensor parameter does not match the speedometer display, replace the IPC.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for IPC replacement, setup, and programming