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 ECM sends the vehicle speed information via high speed GMLAN serial data circuit to the body control module (BCM). The BCM then sends the information via low speed GMLAN to the IPC to order to display the vehicle speed and miles traveled.

Check for the following DTCs:

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Displays and Gages Connector End Views

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

1. Ignition ON, perform the speedometer gage sweep test with the scan tool.

⇒	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, 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.

4. 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