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What are the effects of a faulty rear oxygen sensor on a car?

2 Answers
DiDavid
07/28/25 11:54pm
Engine rear oxygen sensor failure can cause the engine malfunction light to illuminate, and may lead to symptoms such as vehicle shaking with jerking sensations, insufficient power, popping sounds from the exhaust, strong unpleasant odors, car jerking, slow acceleration, inability to reach speed, and increased fuel consumption. Working principle of rear oxygen sensor: The rear oxygen sensor detects the oxygen content in the purified exhaust gas and feeds this information back to the ECU. The computer then compares this data with that from the front oxygen sensor. If the data from the front and rear oxygen sensors are identical (normally the front oxygen sensor signal is greater than the rear), it can be determined that the three-way catalytic converter has failed.
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ElleFitz
08/12/25 4:12am
A faulty rear oxygen sensor can cause significant issues. Last time when my car's sensor failed, the engine warning light on the dashboard immediately lit up, and the exhaust fumes became noticeably more pungent. The main problem is that it can't monitor the three-way catalytic converter's working condition anymore, leading to excessive emissions that would definitely fail the annual inspection. Although the car can still run normally, fuel consumption seems to have increased, with a full tank of gas covering dozens of kilometers less. If left unrepaired for a long time, it could even damage the three-way catalytic converter, and replacing that is much more expensive than replacing the sensor. My advice is not to delay when the warning light comes on—go to the repair shop to read the fault code for confirmation and replace it with an original part as soon as possible for peace of mind.
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Is a rear windshield sunshade illegal?

A rear windshield sunshade is not illegal, but it should be noted that car sunshades can only be installed on the rear side windows. The front side windows are not allowed to have them, as this would obstruct the view of the rearview mirrors. Even highly transparent curtains can still have an impact. Applying Sun Film: If you really feel that the sunlight is too bright when sitting in the front, you can apply a sun film to the glass. This not only effectively blocks some of the heat but also provides a certain degree of explosion-proof protection, making it a win-win solution. Prioritizing Passenger Safety: You can also choose a highly transparent film, which won't affect the rearview mirror's visibility. Otherwise, you may need to cut a triangular window in the film, as passenger safety is always the "top priority." Other Functions of Sunshades: Car sunshades are also known for their ability to effectively reduce sunlight transmission and protect passenger privacy. Especially in hot weather, installing car sunshades is indeed an excellent choice.
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Is a U-turn allowed when there is a dotted line inside the left-turn red light stop line?

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Can a Semi-Automatic Car Be Push-Started If the Battery Dies?

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Does Modifying the Exhaust Increase Fuel Consumption?

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What are the penalties for driving against traffic during congestion?

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