Speedometer Head: Testing and Inspection
INSPECT SPEEDOMETERa. Check the operation.
1) Using a speedometer tester, inspect the speedometer for acceptable indication error and check the operation of the odometer.
NOTICE: Tire wear and over or under tire pressure will affect the indication error.
2) Check the deflection width of the speed meter indicator.
Reference: Below 0.5 km/h (0.3 MPH)
INSPECT OUTPUT SIGNAL OF VEHICLE SPEED
a. Check the output signal wave form.
1) Remove the combination meter assembly with connectors still connected.
2) Connect the oscilloscope to the terminals C10-21 and body ground.
3) Start the engine.
4) Check the signal wave form according to the condition (s) in the table.
OK: As shown in the illustration.
HINT: As the vehicle speed increases, the cycle of the signal waveform narrows.