How to determine if the Exhaust Gas Temperature Sensor is working correctly?

Key points for judging the Exhaust Gas Temperature Sensor

1. Resistance/Voltage Measurement

Use a multimeter to measure the resistance or voltage value across the sensor terminals. Under normal conditions, the resistance should change with temperature in a negative temperature coefficient manner, and the voltage should be in the range of 1.5-3.0V.

2. Ice Water/Hot Water Method

Place the sensor in ice water and observe if the resistance drops significantly; then heat it with hot water, and the resistance should decrease as the temperature rises. If the change is not significant, it may be damaged.

3. On-site Diagnostic Tool Reading

Read the real-time temperature signal through an OBD-II diagnostic tool. The waveform should change smoothly with the engine operating conditions; abnormal fluctuations or signal loss indicate a sensor fault.

4. Heating Element Check

Some exhaust gas temperature sensors have a built-in heating element. Check if its resistance (approximately 5-6 Ω) is normal to prevent signal distortion at low temperatures.
Practical tips: Disconnect the power before measuring the resistance to avoid misreading; maintain good contact with the probes during measurement to prevent contact resistance from affecting the results.