Visual inspection:
1. Check the sensor wiring for damage or loose connections.
2. Inspect the sensor itself for rust, corrosion, or dirt.
Resistance test:
1. Use a multimeter to measure the resistance of the sensor.
2. Consult your repair manual to determine the expected resistance range.
3. If the resistance is out of range, the sensor is faulty.
Voltage test:
1. Use a voltmeter to measure the voltage across the sensor.
2. Idle the engine and count the revolutions per minute (RPM).
3. Consult your repair manual to determine the expected voltage for the appropriate RPM.
4. If the measured voltage does not match the expected value, the sensor is faulty.
Test using a scanner:
1. Connect the OBD2 scanner to the vehicle’s diagnostic port.
2. Read the trouble codes associated with the speed sensor.
3. Perform the tests specified in the repair manual to verify that the sensor is operating correctly.
Other methods:
* Engine speed control: Monitor the tachometer reading on the dashboard while driving. If the readings are irregular or fluctuate, the speed sensor may be faulty.
* Slipping when shifting gears: If the car is slipping when changing gears, it may indicate a faulty speed sensor that is not transmitting accurate wheel speed information to the engine control unit (ECU).
Note: Test steps may vary depending on your vehicle make and model. Always follow the specific manufacturer’s instructions.