Speedometer and/or Odometer Inaccurate or Inoperative
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Speedometer and/or Odometer Inaccurate or Inoperative
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Circuit/System Description
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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 traveled, 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
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Circuit/System Verification
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2.
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If any DTC is set, diagnose this first.
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3.
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Ignition ON, perform the Instrument Cluster Gauge Sweep test with the scan tool, verify that all gauges sweep from their low to high position.
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4.
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If any gauge does not sweep, replace the P16 Instrument Cluster.
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5.
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Drive the vehicle, verify the speedometer gauge value matches the Vehicle Speed parameter on the scan tool.
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6.
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If the value do not match, replace the P16 Instrument Cluster.
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7.
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Drive the vehicle, verify the odometer display, the displayed distance counts up while driving.
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8.
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If the odometer displays only "----" (dashes), go to circuit/system testing.
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9.
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If the odometer display does not count up, verify the K9 Body Control Module and K20 Engine Control Module are functioning correctly. If the K9 Body Control Module and K20 Engine Control Module are working correctly, replace the P16 Instrument Cluster.
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10.
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If all gauges do sweep and display the correct value, and the odometer display counts up, replace the K20 Engine Control Module.
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Note
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If there are multiple modules not original to the vehicle and are not new correctly 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.
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Perform circuit/system verification first.
Instrument Cluster shows "----" (dashes)
Correcting VIN mismatch - odometer is still unlocked.
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1.
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Verify the vehicle odometer status with a scan tool. The reading should be Unlocked.
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2.
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If the reading is Locked, go to correcting VIN mismatch - odometer locked.
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3.
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Using the scan tool, verify the BCM VIN matches the vehicle VIN placard.
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4.
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If the VIN does not match, reprogram the BCM. Then proceed with step 3.
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5.
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Using the scan tool, verify the instrument cluster VIN matches the vehicle VIN placard.
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6.
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If the VIN does not match, reprogram the instrument cluster. Then proceed with step 4.
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7.
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Ignition ON, verify the instrument cluster is displaying the correct value.
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8.
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If the instrument cluster still shows "----" (dashes), replace the P16 Instrument Cluster.
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Instrument Cluster shows "----" (dashes)
Correcting VIN mismatch - odometer is locked.
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1.
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Verify the vehicle odometer status with a scan tool. The reading should be Unlocked.
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2.
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If the reading is Locked, go to step 2.
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3.
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Using the scan tool, verify the instrument cluster VIN matches the vehicle VIN placard.
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4.
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If the VIN does not match, reprogram the instrument cluster. Then proceed with step 3.
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5.
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Perform the BCM setup procedure in SPS.
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6.
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Ignition ON, verify the instrument cluster is displaying the correct value.
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7.
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If the instrument cluster still shows "----" (dashes), replace the P16 Instrument Cluster.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for instrument cluster, BCM or ECM replacement, setup and programming
