Pinpoint Test I: Inaccurate Speedometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test I: Inaccurate Speedometer Indication
Normal Operation
The PCM receives the vehicle speed data from the Output Shaft Speed (OSS) sensor. The Instrument Cluster (IC) receives the vehicle speed signal from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The IC monitors the vehicle speed input from the PCM and commands the speedometer with a corresponding movement of the pointer.
If the IC does not receive the vehicle speed data from the PCM 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 or if the data received is deemed invalid, the IC sets DTC U0100 in continuous memory and defaults the speedometer to 0 km/h (0 mph).
NOTE: If DTC U0100 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 configuration
- Axle ratio configuration
- PCM
- IC
PINPOINT TEST I: INACCURATE SPEEDOMETER INDICATION
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I1 CHECK THE TIRE SIZE AND AXLE RATIO CONFIGURATION
- Enter the following diagnostic mode on the scan tool: Module Programming.
- NOTE: The correct axle ratio and tire size can be found on the vehicle certification label on the LH B-pillar. Refer to Vehicle/Application and ID.
- Verify that the vehicle has the correct tire size and the tire size and axle ratio are correctly configured in the PCM.
- Is the tire size correct and are the tire size and axle ratio parameters correctly configured?
Yes
GO to I2.
No
CONFIGURE the PCM for the correct tire size and axle ratio. TEST the system for normal operation.
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I2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST
- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any PCM DTCs recorded?
Yes
REFER to Computers and Control Systems Information.
No
GO to I3.
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I3 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check for recorded IC DTCs from the self-test.
- Is DTC U0100 recorded?
Yes
Go To Pinpoint Test AT. Pinpoint Tests AT: DTC U0100
No
GO to I4.
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I4 OBSERVE THE SPEEDOMETER OPERATION
- Ignition ON.
- Observe the speedometer while driving the vehicle at various speeds and stopping frequently.
- Does the speedometer begin at 0 km/h (0 mph) and fully return to the 0 km/h (0 mph) position when the vehicle is stopped?
Yes
GO to I5.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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I5 CARRY OUT THE IC 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 and command the speedometer in increments of approximately 10%. Observe the speedometer. The speedometer starts at 0 km/h (0 mph) and moves by approximately 19 km/h (12 mph) (Edge) or 22.5 km/h (14 mph) (MKX) for each 10% increment.
- Does the speedometer begin at 0 km/h (0 mph) and move by approximately 19 km/h (12 mph) (Edge) or 22.5 km/h (14 mph) (MKX) for each 10% increment?
Yes
GO to I6.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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I6 CHECK THE PCM VSS PIDs
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Select the PCM vehicle speed PID (VSS) and monitor the PID while driving the vehicle at various speeds.
- Do the PCM PIDs agree with the speedometer indication?
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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