Speedometer and/or Odometer Inaccurate or Inoperative

SPEEDOMETER AND/OR ODOMETER INACCURATE OR INOPERATIVE

DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM) or the powertrain control module (PCM). The ECM/ECM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The IPC receives a serial data message from the ECM/PCM.

REFERENCE INFORMATION
Schematic Reference
Instrument Cluster Schematics

Connector End View Reference
Instrument Panel, Gages, and Console Connector End Views

Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs

Scan Tool Reference
Scan Tool Data List

Special Tools Required
cell 47852

CIRCUIT/SYSTEM TESTING
1. Install a scan tool
2. Raise the vehicles drive wheels
3. Start the engine
4. Place the transmission into drive
5. With the scan tool, observe the Vehicle Speed Sensor (VSS) parameter in the ECM/PCM Engine Data list.
- If the VSS parameter does not match the speedometer display, replace the instrument panel cluster.
- If the odometer is not operating properly, replace the instrument panel cluster.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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