Pinpoint Test G: Incorrect Speedometer Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test G: Incorrect Speedometer Indication
Normal Operation
The Instrument Cluster (IC) receives the vehicle speed date from the PCM over the communication network. The PCM receives the Vehicle Speed Sensor (VSS) information from the Output Shaft Speed (OSS) sensor. The IC monitors the vehicle speed input from the PCM and commands the speedometer with a corresponding movement of the pointer. The odometer is tamper resistant and accumulates and registers up to one million kilometers in metric mode or one million miles in English mode, based upon rolling count data sent from the PCM over the communication network.
This pinpoint test is intended to diagnose the following:
- Tire size configuration
- Axle ratio configuration
- PCM
- IC
PINPOINT TEST G: INCORRECT SPEEDOMETER INDICATION
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G1 VERIFY THE VEHICLE TIRE SIZE AND AXLE RATIO CONFIGURATION
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Module Programming.
- Select programmable parameters and confirm that the axle ratio and tire size are correctly configured.
- Are the axle ratio and tire size correctly configured?
Yes
GO to G2.
No
CONFIGURE the axle ratio or tire size as required. TEST the system for normal operation.
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G2 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 to continue diagnosis of the DTCs.
No
GO to G3.
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G3 CARRY OUT THE IC SPEEDOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC speedometer (SPDOMETER) active command. Command the speedometer in increments of 10%. Observe the speedometer.
- Does the speedometer begin at 0 km/h (0 mph) and increase by approximately 19 km/h (12 mph)?
Yes
GO to G4.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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G4 CHECK THE PCM VSS PIDs
NOTE: This step may require the use of an assistant to monitor and record the scan tool data.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- NOTE: The speedometer should register approximately the same speed as the VSS PID ± 8 km/h (5 mph).
- Monitor the PCM vehicle speed PID (VSS) while driving the vehicle at 32 km/h (20 mph), 64 km/h (40 mph) and 97 km/h (60 mph).
- Does the speedometer indication agree with the PCM VSS PID within specification?
Yes
INSTALL a new PCM. REFER to Computers and Control Systems Information. 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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