Pinpoint Test F: Incorrect Speedometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Test F: Incorrect Speedometer Indication
Normal Operation
The Instrument Panel Cluster (IPC) receives the vehicle speed signal from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The vehicle speed data originates with the wheel speed sensors. The ABS module provides the wheel speed data to the PCM over the HS-CAN communication bus. The IPC monitors the vehicle speed input from the PCM and commands the speedometer with a corresponding movement of the pointer.
The IPC provides a tolerance that allows the speed indication to display between 3% below and 7% above the actual vehicle speed. This means that with an actual vehicle speed of 96.6 km/h (60 mph), the speedometer may indicate between 93.7-103.3 km/h (58.2-64.2 mph). Incorrect tire size or tire size configuration could potentially affect the speedometer accuracy.
If the IPC receives invalid vehicle speed data from the PCM for 5 seconds or less, the IPC defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the IPC does not receive the vehicle speed data from the PCM for more than 5 seconds, the IPC sets DTC U0100:00 in continuous memory and defaults the speedometer to 0 km/h (0 mph). If the vehicle speed data received is deemed invalid by the IPC, the IPC sets DTC U0401:68 and defaults the speedometer to 0 km/h (0 mph).
NOTE: If DTC U0100:00 sets in the IPC, other observable symptoms may be an inoperative tachometer or odometer.
This pinpoint test is intended to diagnose the following:
- Tire size configuration
- PCM concern
- IPC
PINPOINT TEST F: INCORRECT SPEEDOMETER INDICATION
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F1 CHECK THE TIRE SIZE CONFIGURATION
- Enter the following diagnostic mode on the scan tool: Module Programming.
- NOTE: The correct tire size can be found on the vehicle certification label on the LH B-pillar. Refer to Identification Codes Identification Codes.
- Verify that the size of the tires installed on the vehicle matches the certification label.
- Verify that the tire size configuration matches the certification label.
- Is the tire size correct and is tire size correctly configured?
Yes
GO to F2.
No
INSTALL the correct size tires or CONFIGURE the correct tire size as required. TEST the system for normal operation.
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F2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO SELF-TEST
- Check the recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
- Are any DTCs recorded?
Yes
REFER to Computers and Control Systems. TEST the system for normal operation.
No
GO to F3.
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F3 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST
- Check for recorded IPC DTCs from the self-test.
- Are any DTCs recorded?
Yes
For DTC U0100:00, GO to Pinpoint Test AM. For all other DTCs, REFER to DTC Charts. Pinpoint Tests AM: DTC U0100:00 and P1607:87
No
GO to F4.
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F4 CARRY OUT THE SPEEDOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC DataLogger.
- Select the IPC speedometer (SPDOMETER) active command. Command the speedometer according to the following tables:
Early Build Vehicles and All Vehicles With Part Number Suffix xF
Late Build Vehicles With Part Number Suffix xG and xH
- Does the speed indicated increase within the specified range?
Yes
GO to F5.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Service and Repair. TEST the system for normal operation.
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F5 CHECK THE PCM VSS PIDs
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Select the PCM vehicle speed (VSS) PID and monitor the PID while driving the vehicle at 32 km/h (20 mph), 64 km/h (40 mph) and 97 km/h (60 mph).
- Does the speedometer indicate between 31-34 km/h (19-21 mph), 63-69 km/h (39-43 mph) and 93-103 km/h (58-64 mph) at the 3 PCM PID values?
Yes
GO to F6.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Service and Repair. TEST the system for normal operation.
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F6 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
The speedometer is operating correctly at this time.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Service and Repair. TEST the system for normal operation.
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