What are the causes of rear oxygen sensor problems?
2 Answers
Rear oxygen sensor failures can occur due to the following reasons: 1. System malfunctions when the sensor is infected by a virus; 2. Failure of the catalytic converter; 3. Poor sensor quality, where a surface coating slows down or disables the sensor's response; 4. External carbon buildup or oil contamination, or internal ingress of oil and dust. The rear oxygen sensor is a standard component in vehicles, typically paired with a front oxygen sensor. The front sensor is installed on the exhaust manifold, while the rear sensor is located behind the three-way catalytic converter. The primary function of the oxygen sensor is to monitor the purification efficiency of the three-way catalytic converter by measuring the oxygen content in the post-purification exhaust gases. Effects of a faulty rear oxygen sensor include: 1. Unstable idling; 2. Reduced engine power and sluggish acceleration; 3. Black smoke emission from the exhaust pipe.
I previously encountered a rear oxygen sensor malfunction while repairing my car, primarily caused by pollutant buildup, such as oil stains or carbon deposits covering the sensor surface and blocking detection. Worn-out or damaged wiring leading to short circuits or poor connections is also common, especially in the high-temperature engine compartment. The sensor itself may degrade over time, typically needing replacement after about ten years. Driving on bumpy roads with excessive vibration can damage the sensor. Additionally, using low-quality fuel or cleaning agents with corrosive chemicals can harm it. When this fault occurs, the car triggers error codes, increases fuel consumption, and emits strong exhaust odors, compromising driving safety. I recommend that car owners regularly conduct emission checks, use high-quality fuel, and minimize additives to avoid unnecessary repair costs.
