Signs That Indicate You Need To Replace the Oxygen Sensor

An oxygen sensor, or O2 sensor, is an integral part of the exhaust system. This sensor measures the amount of oxygen present in your vehicle’s emissions and adjusts the fuel ratio to make sure the engine runs optimally and efficiently. Over time, the sensor can get plagued with deposits and send poor readings to the car’s computer.

If your vehicle’s oxygen sensor is no longer performing its role, there are a few signs that you may notice. 

Sign #1: Lowered Engine Efficiency 

A malfunctioning oxygen sensor can lead to poor fuel economy. Since the sensor plays a part in making adjustments to the air-fuel mixture in the engine, it can cause your engine to consume more fuel than necessary when the fuel mixture is too rich. If you’re filling up too frequently, let our professionals check your sensor.

Sign #2: Excess Emissions

A faulty oxygen sensor can also cause more byproducts to spew out of your vehicle. When the engine runs a fuel mixture that is too rich, you may see excess exhaust smoke coming out from the back of your car. Please have your vehicle inspected as it can lead to failed emissions tests.

Sign #3: Illuminated Check Engine Light

One of the most common causes of check engine lights is a bad oxygen sensor. Since it directly sends data to your car’s computer, it can surely trigger the check engine light to come on when it sends misinformation.


If you suspect that your oxygen sensor has gone bad, you should have it checked by a professional technician. We welcome you to Roesbery Car Care in Walnut Creek – we proudly inspect and replace oxygen sensors, using quality parts. Please give us a call or visit our auto repair shop soon!