Every car is equipped with an oxygen sensor. It is an important part that sends the collected data to the car’s computer. The barometric pressure and temperatures are also measured by this sensor, which tells the engine to operate with either a lean or rich mixture.
As this part goes bad, the readings are no longer accurate, and the functionality of your entire car will have to suffer. The exhaust gas is no longer regulated, and the fuel injection levels are completely misplaced. As a result, your car will consume more fuel while also contributing to environmental pollution.
Summary
The most common reason for oxygen sensors to go bad is lead, dirt, and debris. Symptoms of bad sensors are engine misfiring, catalytic converter failure, engine overheating, poor engine performance, and weird engine noises.
A temporary fix for it is removing the plug from the oxygen sensors and connecting a fake one.
The best scanner for testing the bad oxygen sensor is General Technologies Corp GTC ST05 Tester and Simulator.
Other topics covered in this article are :
- How to tell which sensor needs to be replaced
- How to test it with a scanner
- How long does the oxygen sensor last
- Replacement cost
Continue reading this article to know the bad oxygen sensor symptoms. We will teach you how to tell if it’s bad and devise a temporary fix.
A temporary fix
While a complete replacement of this part might be necessary, you can try a temporary fix to be able to drive your car. If the oxygen sensor is not working properly, you will have difficulty commuting to work or cruising down the highway.
You can get under the car and remove the plug from the oxygen sensors. These should be located within the exhaust system. After you find the O2 sensor, rotate them until they are completely removed. Install a fake one while also connecting it to the power socket.
Bad oxygen sensor symptoms
There are some specific symptoms you can look for when you suspect that this part needs to be replaced. With these indications, you will realize whether or not the problem comes from this particular sensor.
We’ll take a look at these symptoms of a bad oxygen sensor.
- Engine misfiring
- Catalytic converter failure
- Engine overheating
- Poor engine performance
- Weird engine noises
1. The engine is misfiring or stalling.

When this component is in perfect working condition, effective combustion is guaranteed. The engine will work without interruptions, and you will not experience any stalling or rough idling. But when the oxygen sensor is failing, you will notice that the engine is often misfiring.
A power loss or complete stalling are common occurrences when the O2 sensor goes bad. These are good indications that you should replace this component, but you should check with a mechanic first.
Error code | Explanation |
P0301 | Misfire in the first cylinder |
P0302 | Misfire in the second cylinder |
P0303 | Several different reasons |
P0304 | A problem caused by the spark plugs and coil packs |
P0305 | Related to the 5th cylinder. |
P0306 | Issues with the air and fuel mix |
2. Catalytic converter failure
Because catalytic converters are part of the exhaust system, they are directly related to the oxygen sensors. When they break down, the catalytic converter will also suffer. Fuel contamination and corrosion can also cause damage to this part.
3. Engine overheating
While it is not a common symptom, engine overheating can also be caused by a failing oxygen sensor. However, you should also consider problems with the electrical system. This symptom appears in the later stages when the owner disregards the first warning signs regarding a failing component.
4. Poor engine performance
Your car will decline in performance as the fuel mixture is completely imbalanced due to the failing part. The loss of power is also caused by the engine misfires and repeated stalling. You should expect to experience these symptoms as your vehicle starts moving from a standing stop.
5. Engine noises
As this component goes bad, you will be able to notice odd and weird sounds coming from the engine bay. A lean mixture results from the lack of air and fuel mixture control. It will cause several noises to emerge as you accelerate your car.
What does the part do?

The oxygen sensor is an important component in your vehicle. It measures the unburnt oxygen in the exhaust and communicates this level to the central computer. The computer can adjust the air-to-fuel ratio with this information to obtain the best performance.
Whether you drive a Ford F150 or a Chevy Silverado, every vehicle needs an oxygen sensor. This part has been mandatory since 1981, but newer vehicles can feature multiple oxygen sensors. As catalytic converters are required on every car, an extra oxygen sensor is used for monitoring this part.
What happens when it goes bad?
When the oxygen sensor goes bad, you will easily notice the symptoms caused by this problem. Firstly, the check engine light will turn on. You can spot this light on your dashboard, and sometimes a specific trouble code will also be shown. Statistically, a bad oxygen sensor is the main reason for check engine lights turning on around the world.
Another negative effect of a broken oxygen sensor is poor acceleration and higher fuel consumption. The engine cannot regulate the mixture itself without the help of this part which sends accurate data to the car’s computer.
Symptoms to look out for
When this component is failing, the dashboard will inform you by lighting up the check engine light. After you notice this warning sign, you should investigate further and try to identify the problem. Check the engine bay for anything suspicious.
You will most likely notice that the oxygen sensor looks different from a brand-new one. It can indicate that you should replace it with a new one.
What causes it?

While the components of a vehicle are strong because they are manufactured from durable materials, they all have a limited lifespan. Eventually, these parts will go bad, and you will have to replace them. The oxygen sensor can get damaged by lead or other additives that are found in the fuel.
Oil and ash can also contribute to faster wear. Debris will interfere with the sensor, and inaccurate readings will be sent to the car’s computer, struggling to adjust the fuel mixture.