What are the symptoms of a frequently failing rear oxygen sensor?
3 Answers
There are several symptoms when a rear oxygen sensor fails: 1. Once the rear oxygen sensor malfunctions, the ECU of the electronic fuel injection system cannot obtain information about the oxygen concentration in the exhaust pipe, thus unable to perform feedback control on the air-fuel ratio. 2. This will lead to increased engine fuel consumption and exhaust pollution, with the engine exhibiting unstable idle, misfires, surging, and other fault phenomena. There are several methods for troubleshooting oxygen sensor faults: 1. Check the resistance of the oxygen sensor heater. 2. Measure the power supply voltage of the oxygen sensor heater. 3. Test the insulation of the oxygen sensor heater to ground. 4. Inspect the signal voltage of the oxygen sensor.
I've been driving for twenty years, and the rear oxygen sensor keeps causing problems, with obvious symptoms. The engine light is always on, that yellow warning light stays lit all day. Fuel consumption keeps rising - it used to be 8 liters per 100 kilometers, but now it's up to 11-12 liters, costing much more in fuel. The car feels powerless when driving, with sluggish acceleration. Even when flooring the pedal uphill, the speed remains slow. The exhaust smells strange too, sometimes like rotten eggs. If this thing keeps failing repeatedly, there might also be abnormal noises or engine vibration. It's best to quickly check for wiring aging or fuel quality issues, don't let it affect the vehicle's lifespan. I often advise friends to pay attention to the chassis when washing the car, as moisture-proofing and rust prevention can help prevent some issues.
From a repair perspective, there are several common symptoms of frequent rear oxygen sensor failures. The check engine light stays on, with the yellow warning light flashing constantly on the dashboard. Diagnostic tools often show a P0138 trouble code. Fuel consumption increases noticeably, engine efficiency drops, and acceleration becomes sluggish with the vehicle feeling heavy. The exhaust pipe may also emit black smoke with a pungent odor, polluting the air. Frequent failures are mostly caused by short circuits in wiring, unstable voltage, or water intrusion into the exhaust system. Having repaired hundreds of vehicles, I recommend checking the sensor ground wire and voltage regulator, and using genuine parts for replacements to ensure durability. Regular carbon deposit cleaning is also crucial.
