How to Check the Oxygen Sensor?
1 Answers
Oxygen sensor inspection methods are as follows: 1. Heater resistance check: Unplug the oxygen sensor wiring harness connector and use a multimeter to measure the resistance at the sensor terminals. If it does not meet the standard, replace the oxygen sensor. 2. Feedback voltage measurement: Unplug the oxygen sensor wiring harness connector. When measuring the feedback voltage, refer to the vehicle's circuit diagram, connect a thin wire from the feedback voltage output terminal of the oxygen sensor, then reconnect the harness connector. Measure the feedback voltage from the wire while the engine is running. 3. Maintain engine speed: Keep the engine running at around 2500 rpm and check if the voltmeter needle swings between 0-1V. Count the number of swings in 10 seconds. Normally, the feedback voltage should fluctuate around 0.45V, with at least 8 changes in 10 seconds. 4. Check for damage to the oxygen sensor: Unplug the oxygen sensor wiring harness connector to disconnect it from the ECU, placing the feedback control system in open-loop mode. 5. Inspect the oxygen sensor's appearance color: (1) Light gray tip: This is the normal color of an oxygen sensor; (2) White tip: Caused by silicon contamination, the oxygen sensor must be replaced; (3) Brown tip: Caused by lead contamination; if severe, the oxygen sensor must also be replaced; (4) Black tip: Caused by carbon buildup. After resolving the engine carbon deposit issue, the carbon on the oxygen sensor can usually clear automatically.
