How to Determine if an Oxygen Sensor is Faulty
2 Answers
Methods to determine if an oxygen sensor is faulty: 1. Increased engine fuel consumption and exhaust pollution, along with symptoms such as unstable idling, misfiring, or surging, indicate a faulty oxygen sensor; 2. Remove the oxygen sensor from the exhaust pipe and check if the vent holes on the sensor housing are clogged or if the ceramic core is damaged. If damage is found, the oxygen sensor should be replaced. The main oxygen sensor includes a heating rod for the zirconia element, which is controlled by the ECU. When the air intake is low (exhaust temperature is low), current flows to the heating rod to warm up the sensor, enabling accurate detection of oxygen concentration.
Last time my car's fuel consumption suddenly soared, and the exhaust had a pungent smell, I realized the oxygen sensor might be faulty. A veteran driver with twenty years of experience tells you to pay special attention to these signs: the engine idles like it's gasping for air and shaking, and you can clearly feel the power being dragged by something when accelerating. If the yellow engine light on the dashboard suddenly comes on, there's an 80% chance it's the sensor failing. At this point, it's best not to delay—use a diagnostic tool to read the fault code immediately. Last time I used an OBD scanner and got the P0130 code, and sure enough, the rear oxygen sensor was completely dead. Remember to check the inner wall of the exhaust pipe after parking; if you find carbon buildup as thick and black as soot from a pot, it’s pretty much confirmed. A mechanic taught me a trick: if black smoke comes out of the exhaust pipe during a cold start, nine times out of ten, the front oxygen sensor is broken.
