Speedometer and/or Odometer Inaccurate or Inoperative
Diagnostic Instructions
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 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.
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 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
Circuit/System Verification
⇒ |
If any DTC is set, diagnose this first. |
2. |
Ignition ON, perform the
Instrument Cluster Gauge Sweep test with the scan tool, verify that
all gauges sweep from their low to high position. |
⇒ |
If any gauge does not sweep, replace the P16
Instrument Cluster. |
3. |
Drive the vehicle, verify the
speedometer gauge value matches the Vehicle Speed parameter on the
scan tool. |
⇒ |
If the value 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 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. |
5. |
If all gauges do sweep and
display the correct value, and the odometer display counts up,
replace the K20 Engine Control Module. |
Circuit/System Testing
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 proper read or
recover the vehicle odometer value. Follow government rules and
documentation (including vehicle identification) regarding
inaccurate/unknown odometer values.
Perform Circuit/System Verification first.
Instrument Cluster is Showing "----" (Dashes)
Correcting VIN mismatch - Odometer is still unlocked
1. |
Verify the vehicle odometer
status with a scan tool. The reading should be Unlocked.
|
⇒ |
If the reading is Locked, go to correcting VIN
mismatch - odometer locked. |
2. |
Using the scan tool, verify
the BCM VIN matches the vehicle's VIN placard. |
⇒ |
If the VIN does not match, reprogram the BCM. Then
proceed with step 3. |
3. |
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. Then proceed with step 4. |
4. |
Ignition ON, verify the
instrument cluster is displaying the correct value. |
⇒ |
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. |
Verify the vehicle odometer
status with a scan tool. The reading should be Unlocked.
|
⇒ |
If the reading is Locked, go to step 2. |
2. |
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. Then proceed with step 3. |
3. |
Perform the BCM setup
procedure in SPS. |
4. |
Ignition ON, verify the
instrument cluster is displaying the correct value. |
⇒ |
If the instrument cluster is still displaying
"----" (dashes), replace the P16 Instrument Cluster. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for instrument cluster, BCM or ECM
replacement, setup and programming
|