Speedometer Head: Testing and Inspection

INSPECT SPEEDOMETER




a. Check the operation.
1. Using a speedometer tester, inspect the speedometer for allowable indication error and check the operation of the odometer.

NOTE: Tire wear and tire over or under inflation will increase 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 input signal wave form.
1. Remove the combination meter with connectors still connected.
2. Connect the oscilloscope to terminal C6-27 and body ground.
3. Start the engine.







4. Check the signal waveform according to the conditions in the table.

OK: As shown in the illustration

HINT: As vehicle speed increases, the cycle of the signal wave form narrows.