Pinpoint Test H: Incorrect Speedometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test H: Incorrect Speedometer Indication
Normal Operation
The PCM receives the vehicle speed data from the Output Shaft Speed (OSS). The PCM provides the Instrument Cluster (IC) with the Vehicle Speed Sensor (VSS) signal over the High Speed Controller Area Network (HS-CAN) communication bus. The IC monitors the VSS input from the PCM and commands the speedometer with a corresponding movement of the pointer. Factors that could potentially affect the accuracy of the speedometer are configurable items such as tire size.
If the vehicle speed data is missing or invalid for 5 seconds or less, the IC defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the IC does not receive the vehicle speed data from the PCM for more than 5 seconds, the IC sets DTC U0101 in continuous memory and defaults the speedometer to 0 km/h (0 mph). If the vehicle speed data received is deemed invalid by the IC for 5 seconds or longer, the IC sets DTC U2023 and defaults the speedometer to 0 km/h (0 mph).
NOTE: If DTC U0101 is set in the IC, other observable symptoms may be an inoperative tachometer, temperature gauge or odometer.
This pinpoint test is intended to diagnose the following:
- Tire size
- PCM
- IC
PINPOINT TEST H: INCORRECT SPEEDOMETER INDICATION
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H1 CHECK THE VEHICLE TIRE SIZE
- Using the certification label located in the LH front door area, verify that the vehicle is equipped with the correct tire size. Refer to Vehicle/Application and ID.
- Does the tire size match the certification label?
Yes
GO to H2.
No
INFORM the customer that tire size affects the accuracy of the speedometer.
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H2 RETRIEVE THE RECORDED DTCs FROM KOEO PCM SELF-TEST
- Check the recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any DTCs recorded?
Yes
REFER to the Computers and Control Systems Information.
No
GO to H3.
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H3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check for recorded IC DTCs from the self-test.
- Are any DTCs recorded?
Yes
For DTC U0101, Go To Pinpoint Test AF. Pinpoint Tests AF: DTC U0101
For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes
No
GO to H4.
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H4 CARRY OUT THE SPEEDOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC speedometer (SPDOMETER) active command. Command the speedometer in 10% increments, while monitoring the speedometer. The speed indicated should increase in increments of approximately 19 km/h (12 mph) for each 10% change.
- Does the speed begin at 0 km/h (0 mph) and increase by 19 km/h (12 mph) for each 10% increment?
Yes
GO to H5.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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H5 CHECK THE IC VSS INPUT
NOTE: An assistant may be required to monitor the scan tool display and the speedometer indication during the test step.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC vehicle speed PID (VSS_IC). Drive the vehicle and monitor the VSS PID at various speeds.
- Does the PID display approximately match the speedometer indication while driving the vehicle?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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