Pinpoint Test F: Incorrect Speedometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Test F: Incorrect Speedometer Indication
Normal Operation
The PCM calculates the vehicle speed from the transaxle Output Shaft Speed (OSS) sensor input and from the tire size and axle ratio configuration in the PCM Vehicle Identification (VID) block. The PCM provides the Instrument Cluster (IC) with the vehicle speed data over the High Speed Controller Area Network (HS-CAN) bus. The IC (Instrument Cluster) monitors the vehicle speed input and commands the speedometer with a corresponding movement of the pointer.
The IC (Instrument Cluster) provides a tolerance which biases the speed indication and allows the gauge to display between 3% lower and 7% higher than 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). Other factors that could potentially affect the speedometer accuracy are incorrect tire size, tire size configuration and axle ratio configuration.
If the vehicle speed data is missing for 5 seconds or less or if the IC (Instrument Cluster) receives invalid vehicle speed data for 5 seconds or less, the IC (Instrument Cluster) defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the IC (Instrument Cluster) does not receive the vehicle speed data from the PCM for more than 5 seconds, the IC (Instrument Cluster) sets DTC U0100 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 (Instrument Cluster) for 5 seconds or longer, the IC (Instrument Cluster) sets DTC U2023 and defaults the speedometer to 0 km/h (0 mph).
NOTE: If DTC U0100 is set in the IC (Instrument Cluster), other observable symptoms may be an inoperative tachometer, temperature gauge or odometer.
This pinpoint test is intended to diagnose the following:
- PCM concern
- IC (Instrument Cluster)
PINPOINT TEST F : INCORRECT SPEEDOMETER INDICATION
F1 CHECK THE TIRE SIZE CONFIGURATION
- Enter the following diagnostic mode on the scan tool: PCM Programmable Parameters.
- NOTE: The correct tire size can be found on the vehicle certification label on the LH B-pillar.
Verify that the vehicle has the correct tire size according to the certification label and the tire size is correctly configured in the PCM.
Is the tire size correct and is tire size parameter correctly configured?
Yes
GO to F2.
No
CONFIGURE the PCM for the correct tire size. TEST the system for normal operation.
F2 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO (Key ON Engine OFF) SELF-TEST
- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.
Are any DTCs recorded?
Yes
DIAGNOSE all PCM DTCs first. REFER to the Computers and Control Systems Information.
No
GO to F3.
F3 RETRIEVE THE RECORDED DTCs FROM THE IC (Instrument Cluster) SELF-TEST
- Check for recorded IC (Instrument Cluster) DTCs from the self-test.
Are any DTCs recorded?
Yes
For DTC U0100, GO to Pinpoint Test AO. Pinpoint Test AO: DTC U0100
For DTC U2023, RETRIEVE and REPAIR all non-network DTCs in the PCM and other modules on the network. REFER to the Computers and Control Systems Information and Body Control Systems for a list of all DTCs.
For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes
No
GO to F4.
F4 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 F5.
No
INSTALL a new IC (Instrument Cluster). REFER to Instrument Cluster (IC) . TEST the system for normal operation.
F5 CARRY OUT THE IC (Instrument Cluster) SPEEDOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC (Instrument Cluster) DataLogger.
- Select the IC (Instrument Cluster) 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 approximately 20 km/h (12 mph) for each 10% increment.
Does the speedometer indication match the scan tool display?
Yes
GO to F6.
No
INSTALL a new IC (Instrument Cluster). REFER to Instrument Cluster (IC) . TEST the system for normal operation.
F6 CHECK THE PCM VSS (Vehicle Speed Sensor) PID
- 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
The speedometer is operating correctly at this time.
No
INSTALL a new IC (Instrument Cluster). REFER to Instrument Cluster (IC) . TEST the system for normal operation.