Buick Regal: Speedometer and/or Odometer Malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• 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 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 serial data to the body control module (BCM). The BCM then sends the information via serial data 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.

Diagnostic Aids

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.

Reference Information

Schematic Reference

Instrument Cluster Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Master Electrical Component List

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

1. Ignition ON/Vehicle in Service Mode.

2. Verify no DTC is set.

• If any DTC is set

Diagnose DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle.

• Go to next step: If no DTCs are set

4. Verify the speedometer gauge value matches the scan tool Vehicle Speed parameter while driving the vehicle.

• If the values do not match

Replace the P16 Instrument Cluster.

• Go to next step: If the speedometer value matches the scan tool parameter

5. Verify the odometer display and the displayed distance counts up while driving the vehicle.

• If the odometer displays only "----" (dashes)

Refer to Circuit/System Testing.

• If the odometer display does not count up

Replace the P16 Instrument Cluster.

• Go to next step: If speedometer sweeps and displays the correct value, and the odometer display counts up

6. All OK.

Circuit/System Testing

NOTE:

• Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
• If there are multiple modules not original to the vehicle and they are used or incorrectly configured service parts, SPS may not be able to proper read or recover the vehicle odometer value. Follow government rules and documentation (including vehicle identification) regarding inaccurate/unknown odometer values.

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

1. Ignition ON/Vehicle in Service Mode.

2. Verify the scan tool Odometer Status parameter is Unlocked.

• If the reading is Locked

Refer to correcting VIN mismatch - odometer locked.

• Go to next step: If the reading is Unlocked

3. Verify the scan tool BCM VIN parameter matches the vehicle's VIN placard.

• If the VIN does not match

Reprogram the BCM, then proceed to Step 3.

• Go to next step: If the VIN matches

4. Verify the scan tool Instrument Cluster Vehicle Identification Number (VIN) parameter matches the vehicle's VIN placard.

• If the VIN does not match

Reprogram the instrument cluster. Then proceed with step 4.

• Go to next step: If the VIN matches

5. Verify the instrument cluster is displaying the correct value.

• If the instrument cluster is still displaying "----" (dashes)

Replace the P16 Instrument Cluster.

• Go to next step: If the instrument cluster is displaying the correct value

6. All OK.

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

1. Ignition ON/Vehicle in Service Mode.

2. Verify the scan tool Odometer Status parameter is Locked.

• If the reading is Unlocked

Refer to Correcting VIN mismatch - odometer unlocked.

• Go to next step: If the reading is Locked

3. Verify the scan tool Instrument Cluster Vehicle Identification Number (VIN) parameter matches the vehicle's VIN placard.

• If the VIN does not match

Reprogram the Instrument Cluster. Then proceed with step 3.

• Go to next step: If the VIN matches

4. Perform the BCM setup procedure in SPS.

5. Verify the instrument cluster is displaying the correct value.

• If the instrument cluster is still displaying "----" (dashes)

Replace the P16 Instrument Cluster.

• Go to next step: If instrument cluster is displaying the correct value

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

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