Volt

Speedometer and/or Odometer Malfunction

The instrument cluster displays the engine coolant temperature, fuel level, vehicle speed and the engine speed based on the information from the engine control module (ECM). The ECM sends information via a High Speed CAN-Bus signal to the body control module (BCM). The BCM then sends the information via a Low Speed CAN-Bus signal to the instrument cluster to display the engine coolant temperature, fuel level, the engine speed, the vehicle speed and the distance travelled, either in kilometers or miles, based on the vehicle requirements. The instrument cluster will display dashes when its VIN does not match the VIN received from the BCM.

If the VIN mismatch is corrected the odometer will once again be displayed in the instrument cluster. If the vehicle is driven for a calibrated distance with a VIN mismatch, it will cause the instrument cluster odometer to enter into an error mode and lock itself. When this occurs the dashes will remain on the display even after correcting the VIN mismatch. The vehicle odometer status data display on the scan tool can be used to identify a locked odometer. The only way to unlock the instrument cluster (clear the dashes from the display) is to perform an SPS programming event. Failure to follow the diagnostic and programming procedures may result in either an improper odometer value or a module replacement.

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Verify no DTC is set.

⇒	If any DTC is set, diagnose this first.

2. Vehicle in Service Mode, perform the Instrument Cluster Gauge Sweep test with the scan tool, verify that the instrument cluster performs a screen test sequence.

Note: Since there are no gauges, the instrument cluster will go through a screen test sequence instead of sweeping the gauges.

⇒	If the instrument cluster does not perform the screen test sequence, replace the P16 instrument cluster.

3. Drive the vehicle, verify the speedometer value matches the Vehicle Speed parameter on the scan tool.

⇒	If the values do not match, replace the P16 instrument cluster.

4. Drive the vehicle, verify the odometer display, the displayed distance counts up while driving.

⇒	If the odometer displays only "----" (dashes), go to circuit/system testing.

⇒

If the odometer display does not count up, verify the scan tool Body Control Module Odometer parameter and scan tool Engine Control Module Odometer parameter are functioning correctly. If the Engine Control Module Odometer parameter does not count up while driving, replace the K20 engine control module. If the Body Control Module Odometer parameter does not count up while driving, replace the K9 BCM. If the K9 BCM and K20 Engine Control Modules are working correctly, replace the P16 instrument cluster.

Note: If there are multiple modules not original to the vehicle and are not new correctly configured service parts, SPS may not be able to properly read or recover the vehicle odometer value. Follow government rules and documentation (including vehicle identification) regarding inaccurate/unknown odometer values.

Instrument Cluster is Showing "----" (Dashes, Correcting VIN mismatch - odometer is still unlocked.)

1. Verify the vehicle odometer lock status with a scan tool. The reading should be Inactive.

⇒	If the reading is Active, go to correcting VIN mismatch - odometer is locked.

2. Using the scan tool, verify the BCM VIN matches the vehicle VIN placard. If the VIN does not match, reprogram the BCM.
3. Using the scan tool, verify the instrument cluster VIN matches the vehicle VIN placard. If the VIN does not match, reprogram the instrument cluster.

⇒	If the instrument cluster is still displaying "----" (dashes), replace the P16 instrument cluster.

Instrument Cluster is Showing "----" (Dashes, Correcting VIN mismatch - odometer is locked)

1. Using the scan tool, verify the instrument cluster VIN matches the vehicle's VIN placard. If the VIN does not match, reprogram the instrument cluster.
2. Perform the BCM setup procedure in SPS.
3. Vehicle in Service Mode, verify the instrument cluster is displaying the correct odometer value.

⇒	If the instrument cluster is still displaying "----" (dashes), replace the P16 instrument cluster.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for instrument cluster, BCM or ECM replacement, programming and setup