Diagnostic Instructions
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 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.
Diagnostic Aids
Check for the following DTCs:
Reference Information
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
Circuit/System Testing
- 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. |
- Ignition OFF, raise the vehicles drive wheels.
- 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. |
- 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.
Control Module References
for IPC replacement, setup, and programming