what happens to a car when the oxygen sensor is bad

Oxygen sensor plays an important role in every car. Therefore, you need to know what happens to a car when the oxygen sensor is bad.

Before going deep down regarding the subject, let’s focus on what it is?

How does an Oxygen Sensor work?

Your vehicle engine control unit (ECU) must know the exhaust gas composition for proper fuel consumption. Exhaust gases are a mixture of several gaseous compounds like Oxygen and Carbon. Among them, oxygen needs to ignite the fuel to run the car. Same as we fill fuel into the vehicle, we should have an idea of the amount that reached the engine for the ignition.

At the exhaust manifold, there is equipment called the oxygen sensor. Some vehicles, especially new formulated pickup sport type vehicles, contain two units. Those two sensor units in the engine are near the exhaust manifold, and the other is near the catalytic converter. Other vehicles obtain only one unit. This special component measures the oxygen level in the exhaust gas mixture.

Once it detects the O2 concentration at the above mixture, it sends the amount back to the engine control unit. This engine control module act as a computer in the vehicle that can manage all the driving and engine operations.

Once this computer receives the information, it will make the proper adjustments for efficient duel burning. If not, you cannot get the maximum output of gasoline burning in the engine. You can say it as an incomplete burning.

Mazda BJ5P Main Oxygen Sensor
Mazda BJ5P Main Oxygen Sensor

How do I know if I have a bad Oxygen sensor?

If anything happens to this sensor, there will be few issues arrive. Because it is one of the important components in every vehicle. So, you will face several driving issues while driving.

Those symptoms are very common and easy to recognize. Thanks to those symptoms, you will be able to find those issues before they get worse.

Now we will take you to top bad O2 sensor symptoms.

You can see the indication of check engine light

Normally the bad oxygen sensor is the number one reason for indicating engine light in your dashboard. The engine light alerts that your car is experiencing issues. When you see such an indication, you need to check the vehicle immediately. Because some issues in the engine are severe than others. And apart from the sensor issue, engine light active indicates a lot of engine troubles. But we recommended that you not operate the engine alone if you have not any sufficient practical knowledge. For better result, take the help of an experienced mechanic.

Engine Check Light indication
Engine Check Light indication

Bad fuel economy

As a result of the previously mentioned issue, your vehicle is starting to burn more fuel than the usual rate. Because your engine control unit has no idea about the amount of oxygen available for ignition. It tends to supply as much as fuel it can towards the engine. The resultant effect is a higher rate of fuel consumption.

You can track this issue because it decreases the fuel tank more rapidly than on a normal day. It will badly affect both your wallet and the environment. As above mentioned, more gasoline release into the environment. Also, incomplete burning of them increases the toxicity of the emission gas collection from the car.

A rotten egg smell from the engine

Because of the oxygen sensor malfunctioning, we talk about the bad fuel economy. So, these extra amounts of higher gasoline volume can cause to release of Sulphur Dioxide gas. You can smell the gas as rotten egg smell.

Sometimes you will experience a black smoke emission from your exhaust. You can identify either one of the symptoms easily. Those smoke and smell never good for your car’s other systems. So, keep in mind to check your vehicle as soon as possible when you notice those issues.

Rough Idling

Your vehicle’s O2 sensor controls engine timing, combustion intervals and air to fuel ratios. So, the component malfunctioning jams every operation related to those. Also, your car does not run steady when it is stopped or parked. As a result, you will experience roughness when idling or operating the car. Suppose you stop the car in road traffic, and suddenly you need to pick up the engine to go; car acceleration does not work well.

Your engine misfire

When you are driving, you will feel the non-steady mode of acceleration. When you try to pick up the engine, it will not reach the expected speed level. Even you paddle the accelerator tightly. Your speed will not increase. You can collectively say sudden engine acceleration will not work in this situation.

How to tell which oxygen sensor needs to be replaced?

Before replacing or take a solution against the sensor component, you need to scan the vehicle’s engine.

So, we recommended that you fix the matter with the help of proper technicians, equipment and technology. Once your vehicle engine control computer unit connects to the scanner, a special indication will alert. The message is ‘system too rich bank one’. If it displays, you can remove the main oxygen sensor to replace a new one.

Main Oxygen Sensor Location inside the Engine
Main Oxygen Sensor Location inside the Engine

As previously mentioned, there are two oxygen sensors in some vehicles. If another oxygen sensor has to change, the error message will be changed as ‘system too rich bank two’. Then you need to change the other one. Because how to tell which oxygen sensor needs to be replaced is a little difficult at first glance.

Although you already replaced new units, still there can be error indications sometimes. Then you need to go for issues related to other parts like non-proper engine tune-up, Damage engine plugs, sparks in ignition coils and malfunctioning in the fuel pump.

Ignition coils of Mazda BJ5P Car
Ignition coils of Mazda BJ5P Car

More trials and assumptions should be there to make it possible. Normal O2 sensor should be replaced every 60000 to 90000 miles from the beginning. So, have to replace the component is a natural process.

But keep in mind, once you experience those errors after replacing both sensors, there should be another error other than the sensor. So, checking the vehicle with proper technology and technicians will help to find the exact issue.

How Much Does It Cost to Replace an O2 Sensor?

Please do not wait until the O2 sensor damage in full capacity to replace it. Because it badly affects other important components in the engine. Also, it will harm both your wallet and the environment. So, once you realize your sensor will start to blame your system, you need to place it. If not, you will have to pay thousands of dollars to maintain and replace another important component in the engine.

The general replacement cost of this component is $250 to $400. But it depends on the make, year, and model of the vehicle. The total cost of $250 to $400 consists of both labor cost and renew part cost. But this amount is not a huge amount when compared to the cost of other important parts in the engine. Also, proper replacement saves your vehicle operations at an optimal state. So do not worry about How Much Does It Cost to Replace an O2 Sensor for saving your car.

Can You Drive Your Car with A Bad O2 Sensor?

Yes. Of course. But do not do. Because of the wellness of your wallet, environment and for your vehicle long-lasting, do not drive without replacing it. As mentioned earlier, your engine will generate power by a rich fuel blend because it is blind without the oxygen amount information in the exhaust. Same as mentioned, you will face a lot of driving issues while driving. But yes, you can drive still. But it is recommended not to drive your vehicle with those issues for more than a few days. And if you continuously ignore the error messages, you will damage your vehicle in greater amounts.

As a result, in the end, you will have to replace even more costly components like the catalytic converter of the engine. So do not make it too worst. Simply replace and keep healthy the vehicle.

And for last, do not think only about yourself. You are making a severe environmental impact without replacing it. So, think wisely about what happens to a car when the oxygen sensor is bad. We have provided enough information for the right direction.


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