Replace Oxygen Sensor Check Engine Light Came Back (Explained)

If your check engine light is coming on the whale you are driving, you have to head over to a local auto store to run a diagnostic so that they can find the cause of the check engine light. These auto shops will plug a small computer underneath your dashboard, and they will read back a code why the check engine light is turned on. There are plenty of reasons why your check engine light is turning on. 

So in this article, we’ll focus on the check engine light that would come back after replacing the oxygen sensor. Let us get started. 

Replace Oxygen Sensor Check Engine Light Came Back

Why Does Replace Oxygen Sensor Check Engine Light Come Back?

This is a common question, and it does not have only one reason. There are plenty of reasons why this would happen. First, the light will not turn off immediately. 

Second, there must be tests to run, which should be passed. Some tests would require specific driving auditions to run—research of OBDII drive cycle for intensive information. Third, there might be a problem with the part you have replaced. 

It might not be related to a bad oxygen sensor. Some codes are erroneously called oxygen sensor codes, and they are fuel trim codes. 

There is also an oxygen sensor failure. This is a common mistake. There might be a fault code related to the bank one sensor two heater circuit. 

How To Fix That Replace Oxygen Sensor Check Engine Light Comes Back?

In fixing the check engine light that comes back on after replacing the oxygen sensor, there are plenty of reasons for it. So you need to know the only problem to fix based on that problem. First, you might have to replace your oxygen sensor. 

An oxygen sensor monitors unburned oxygen from the exhaust of your vehicle. This will help monitor how much fuel is being burned in the engine’s cylinder. There is a faulty sensor, and it will not provide the correct information on your computer that will decrease the gas mileage of your vehicle. 

Over time, the sensor will be covered in oil ash. This will then reduce the ability of the sensor to adjust the oxygen and the fuel mixture. There might be a loose or broken gas cap. 

The gas cap is essential. If the gas cap is cracked or broken, the fuel vapors will leak out, and it will cause problems for the fuel system of your vehicle. It will reduce fuel efficiency and will increase the emission. If there is an error pointing to the fuel cap, this could mean that the fuel vapors are leaking out of your cap.

You might also have a catalytic converter failure. The purpose of this catalytic converter is to reduce exhaust gasses. They will convert the carbon monoxide and other harmful materials into an inert compound. 

You might also need to replace the mass airflow sensor. A mass airflow sensor will inform your vehicle’s computer to mix the right amounts of fuel and air-based upon the mixture required by the engine. Finally, you might need to replace your spark plugs and the wires. 

The spark plugs are installed in the valve chamber of the vehicle. There is a seal required around the plug, and there is a gap for the spark.

How Many Miles Do You Have To Drive To Reset The Oxygen Sensor?

This will vary with the manufacturer. It can be for a trip cycle or up to three cycles. Chevy seems to take about eighty miles, said some people in everyday driving. 

How Do You Reset The Check Engine Light After Changing The O2 Sensor?

The 02 sensor in your car is the one that monitors the exhaust gasses that are coming out of your engine. This will determine the amount of oxygen in the gasses and indicate how well the fuel is burning. The 02 sensors will send information into the electronic control unit or the ECU. 

The ECU will then adjust the air to fuel ratio and optimize the fuel combustion. Sometimes, the 02 sensors might fail. And sometimes, you might need to change it. 

If you have replaced your 02 sensors, you will reset the ECU. The first step is to open the fuse panel. It is located in the driver-side footwell. 

It is under the steering column. Pull it down with your fingers. Find the fuse location for the ECU while using the fuse diagram under the side of the fuse panel cover. 

Then, pull the fuse for the ECU using the fuse pullers in the fuse panel. Next, turn the ignition to the o position but not crank the engine yet. 

Wait for about five minutes and then reinsert the fuse. The check engine light will blink, and then it will shut off. This is an indication that your ECU is reset.

Oxygen Sensor Codes Keep Coming Back: What To Do?

Usually, if your oxygen sensor codes keep on coming back, your 02 sensor is not at fault and can be because of anything. It can be a bad spark plug or a bad mistake. This is an essential part of checking the chain of things. 


In summary, many car drivers are experiencing a check engine light that is coming back on after replacing their oxygen sensors. There are plenty of reasons for this situation to happen. 

That is why it is essential to find out first what the actual reason is. Only then can you identify the solution.

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Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more