GM Service Manual Online
For 1990-2009 cars only

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle

Circuit/System Description

The instrument panel cluster (IPC) calculates the mileage based on the vehicle speed signal circuit from the engine control module (ECM). The ECM sends the vehicle speed information via high speed GMLAN serial data to the body control module (BCM). The BCM then sends the information via low speed GMLAN to the IPC indicating the value of the odometer. The odometer will display 'error' if an internal memory failure is detected. The odometer displays either miles or kilometers and the desired units can be accessed by pressing the trip/reset switch.

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

Circuit/System Testing

  1. Ignition OFF, disconnect the driver information center (DIC) switch connector.
  2. Test for less than 1 ohm of resistance between the DIC switch ground circuit and ground.
  3. If greater than 1 ohm, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Trip Reset Switch parameter is Inactive.
  5. If not inactive, test the signal circuit for a short to ground. If the circuit tests normal, replace the IPC.
  6. Install a 3-Amp fused jumper wire between the signal circuit and ground. Verify the scan tool Trip Reset Switch parameter is Active.
  7. If not active, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
  8. If all circuits test normal, test or replace the DIC switch.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification

Control Module References