What Happens When an Oxygen Sensor Fails?
2 Answers
Here are the symptoms that may occur when an oxygen sensor is damaged: 1. The engine warning light remains illuminated when the ignition is in the ON position. 2. A small amount of black smoke is emitted when gently pressing the accelerator pedal, while a large amount of black smoke is emitted during rapid acceleration. 3. If the vehicle experiences reduced power, difficulty accelerating, unstable idle speed during operation, and excessive emission of pollutants, these may all be signs of a faulty oxygen sensor. 4. Fault code: P01D6 (intake pressure sensor voltage below the lower limit). Abnormal intake pressure signal prevents the ECU from receiving accurate intake air volume information, leading to abnormal fuel injection. This results in incomplete combustion, reduced engine power, and black smoke emission during acceleration. Both wiring harness connection issues and sensor failure can cause this fault.
A faulty oxygen sensor can be a real headache. With over a decade of driving experience, I've encountered this issue where the check engine light stays on constantly, and the car feels sluggish when accelerating—like the throttle isn't responding. Fuel consumption skyrockets ridiculously; my usual city driving consumption of 8 liters per 100 km suddenly jumped to over 10 liters, hitting my wallet hard. A knowledgeable friend explained that the oxygen sensor acts like the car's nose—when it fails, it can't accurately detect exhaust oxygen levels, causing the ECU to incorrectly adjust the fuel mixture. This leads to either excessive fuel waste or insufficient fuel, resulting in black smoke and a choking smell. If left unrepaired long-term, the catalytic converter can corrode and fail, costing over a thousand yuan to fix—much more expensive. Plus, failing emissions tests during annual inspections becomes another hassle. I replaced the sensor promptly for just around 200 yuan, and the engine smoothed out while the warning light turned off. My advice: don't ignore it—small issues can escalate into costly problems. Regular check-ups are best for prevention, especially for older car owners.
