Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The ECM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The PCM sends the vehicle speed information via GMLAN serial data circuit to the body control module (BCM). The BCM sends the GMLAN message to the IPC in order to control the speedometer gage and display the vehicle speed and miles traveled.

Check for the following DTCs:

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Instrument Panel, Gages, and Console Connector End Views

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

1. Ignition OFF, raise the vehicles drive wheels.
2. Engine ON, transmission in drive, 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.

3. Verify that the odometer is operating properly.

⇒	If the odometer is not operating properly, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for IPC replacement, setup, and programming