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How to replace an oxygen sensor in car – All you need to know

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Is your car’s check engine light on? After examining your engine, if you’re still unable to detect the problem, a bad oxygen sensor could be the reason. What’s an O2 sensor and how to replace an oxygen sensor – we’ve mentioned all you need to know about O2 sensors in the post.   

Replacing an O2 sensor in your vehicle is no biggie. With a little know-how, you can replace it at home without any hassle. Before we let you know the O2 sensor removal tricks and process, here are the most frequently asked questions about oxygen sensors and their answers.    

What is an oxygen sensor?   

An oxygen sensor, also called an O2 sensor is an electronic device located in the exhaust system. The oxygen sensor checks the amount of O2 that exits out of the exhaust, and it also plays a vital role in determining the air-to-fuel ratio in the engine. Depending on the model and manufactured year, there will be 1-4 oxygen sensors in your car.  

How to replace an oxygen sensor - picture of n oxygen sensor

When should you replace the O2 sensor?   

You don’t have to change the O2 sensors in the car every time you take it for a service or while following the car maintenance schedule. Change when the sensors malfunction or when they are damaged. Here are the signs that point towards a fault in O2 sensors:  

  • If the check engine light is on   
  • A significant increase in your vehicle’s fuel consumption  
  • Trouble starting the vehicle   
  • A rough idle  
  • Your spark plugs could be misfiring  
  • Poor acceleration  
  • If you notice black smoke exiting from the exhaust   
  • If you smell rotten eggs or sulfur smell from the exhaust  

Can I drive with a bad oxygen sensor?   

Although a faulty O2 sensor will not stop you from driving, it’s best to replace it as soon as possible. That’s because a faulty oxygen sensor can increase fuel consumption, which means you need to shell out more money on gas – we’re sure you don’t want to do it. Also, the malfunctioning sensor can damage the engine over time, and engine damages are often expensive.   

Should I change all the sensors if one gets damaged?   

No, you don’t have to replace the entire set. Change only the malfunctioning O2 sensor.   

How much does an O2 sensor cost?   

The rates differ based on the vehicle and the year of your car. On average, an O2 sensor should cost you $20 to $100.   

How much does oxygen sensor replacement cost if I get it done professionally?   

Depending on the time taken, professionals will charge you anywhere between $50 to $100 as a labor charge. Replacing the sensors usually takes very little time, and with a little know-how, you can change it yourself.   

How to replace an oxygen sensor?   

Step 1  

Use an OBD scanner to find out which sensor is malfunctioning. You can buy an OBD scanner online or at any auto parts store near you. If you don’t want to invest in one, you can seek the mechanic’s help to detect the code.   

Step 2  

Park your vehicle on a flat surface, and if your engine was running recently, let it cool. The hot components can burn your fingers. Therefore, it’s best to let the engine cool for at least 30 minutes before you touch it.   

Step 3  

Jack up your vehicle and locate the sensor to remove it. Most modern vehicles have two sensors near the motor and two near catalytic converters, and it will look like a spark plug with black wires coming out of it.   

Step 4  

Now unplug the sensor from the wiring connection. The sensor could be tight, so to remove it easily, spray some penetrating oil or WD-40 and let it sit for some time.   

Step 5  

Use a ratchet wrench and an oxygen sensor socket to unscrew it. You can also use an open-end wrench to unscrew the sensors.  

Step 6  

Place the new sensor and screw it back. Don’t forget to connect the electrical wires back to the sensor.   

Step 7  

Take the car for a ride. After some time, the check engine light should turn off. If this happens, it means you’ve completed the oxygen sensor replacement task.   

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