Speedometer and/or Odometer Inaccurate or Inoperative

Speedometer and/or Odometer Inaccurate or Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 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.

Diagnostic Aids

Check for the following DTCs:

* DTC B1000
* DTC B1009
* DTC U2100
* DTC U2103
* DTC U2105-U2199

Circuit/System Testing

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.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for IPC replacement, setup, and programming