Pinpoint Test G: Incorrect Speedometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Test G: Incorrect Speedometer Indication
Normal Operation
The Instrument Panel Cluster (IPC) receives the Vehicle Speed Sensor (VSS) signal from the PCM (non-hybrid) or from the Transmission Control Module (TCM) (hybrid) over the High Speed Controller Area Network (HS-CAN) communication bus. The PCM or TCM (Transmission Control Module) receives the VSS (Vehicle Speed Sensor) input from the Output Shaft Speed (OSS). The IPC (Instrument Panel Cluster) monitors the VSS (Vehicle Speed Sensor) input from the PCM or TCM (Transmission Control Module) and commands the speedometer with a corresponding movement of the pointer.
The IPC (Instrument Panel Cluster) provides a tolerance which biases the speed indication and displays between 3% below and 7% higher than 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 IPC (Instrument Panel Cluster) receives invalid vehicle speed data for 5 seconds or less, the IPC (Instrument Panel Cluster) defaults the speedometer to the last setting, based upon the last known good vehicle speed message. If the IPC (Instrument Panel Cluster) does not receive the vehicle speed data for more than 5 seconds, the IPC (Instrument Panel Cluster) sets DTC U0100:00 (non-hybrid) or U0101:00 (hybrid) 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 (Instrument Panel Cluster) for 5 seconds or more, the IPC (Instrument Panel Cluster) sets DTC U0401:68 (non-hybrid) or U0402:68 and defaults the speedometer to 0 km/h (0 mph).
Factors that could potentially affect the accuracy of the speedometer are configurable items such as axle ratio and tire size.
NOTE: If DTC U0100:00 is set in the IPC (Instrument Panel Cluster) , 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 or driveline type configuration
- PCM concern
- IPC (Instrument Panel Cluster)
PINPOINT TEST G : INCORRECT SPEEDOMETER INDICATION
G1 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), indicate the different vehicle speeds and fully return to the 0 km/h (0 mph) position when the vehicle is stopped?
Yes
GO to G2.
No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.
G2 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.
Select programmable parameters and 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 the tire size parameter correctly configured?
Yes
GO to G3.
No
CONFIGURE the tire size. TEST the system for normal operation.
G3 CHECK THE AXLE RATIO OR DRIVELINE TYPE CONFIGURATION
- Enter the following diagnostic mode on the scan tool: Module Programming.
- Select programmable parameters and verify that the axle ratio or driveline type is correctly configured in the PCM.
Is the axle ratio or driveline type parameter correctly configured?
Yes
GO to G4.
No
CONFIGURE the axle ratio or driveline type. TEST the system for normal operation.
G4 RETRIEVE THE RECORDED DTCs FROM THE PCM AND TCM (Transmission Control Module) KOEO (Key ON Engine OFF) SELF-TEST
- Check for recorded PCM and TCM (Transmission Control Module) DTCs from the Key ON Engine OFF (KOEO) self-test.
Are any DTCs recorded?
Yes
DIAGNOSE all PCM and TCM (Transmission Control Module) DTCs first. REFER to Computers and Control Systems Information.
No
GO to G5.
G5 RETRIEVE THE RECORDED DTCs FROM THE IPC (Instrument Panel Cluster) SELF-TEST
- Check for recorded DTCs from the IPC (Instrument Panel Cluster) self-test.
Are any DTCs recorded?
Yes
For DTC U0100:00 (non-hybrid), GO to Pinpoint Test BF. Pinpoint Test BF: DTC U0100:00
For DTC U0100:01 (hybrid), GO to Pinpoint Test BG. Pinpoint Test BG: DTC U0101:00
For DTC U0401:68 (non-hybrid) or U0402:68 (hybrid), RETRIEVE and REPAIR all non-network DTCs in the PCM and other modules on the network. REFER to 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 G6.
G6 CARRY OUT THE IPC (Instrument Panel Cluster) SPEEDOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IPC (Instrument Panel Cluster) DataLogger.
- Select the IPC (Instrument Panel Cluster) speedometer (SPDOMETER) active command. Command the speedometer according to the following table while monitoring the speedometer.
Speedometer Command Gauge Position 0% 0 km/h (0 mph) 10% 19 km/h (12 mph) 20% 39 km/h (24 mph) 30% 58 km/h (36 mph) 40% 77 km/h (48 mph) 50% 97 km/h (60 mph) 60% 116 km/h (72 mph) 70% 135 km/h (84 mph) 80% 154 km/h (96 mph) 90% 174 km/h (108 mph) 100% 193 km/h (120 mph)
Does the speedometer indicate the approximate speed according to the above specifications?
Yes
GO to G7.
No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.
G7 CHECK THE PCM VSS (Vehicle Speed Sensor) 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
The speedometer is operating correctly at this time.
No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.