Symptoms Of Bad O2 Sensor Chevy – All You Need To Know!

Are you experiencing some weird symptoms like the car is running rich and there is a strong smell of gas from the exhaust? Well, you might be experiencing some symptoms of bad O2 sensor Chevy. But you shouldn’t worry because we are going to help you tackle this problem.

• What Is O2 Sensor?
• How It Works?
• Upstream
• Downstream
• Symptoms
• Testing
• Cost
• Conclusion

Doing a proper research before you decide on spending a ton of money fixing a problem might be a really good idea. There are a ton of people who would replace an O2 sensor without knowing whether this sensor is upstream, downstream, or even whether or not they have the right sensor.

This is why you shouldn’t be one of these people and you should always do proper research before you jump into solving problems. Especially sensor-related issues like in this case. So, this is why we are going to help you out when it comes to understanding everything about O2 sensors in general as well as the symptoms of bad O2 sensor Chevy.

First, we are going to cover what’s O2 sensor and then we will learn how O2 sensor works, after that, we are going to discuss both upstream and downstream O2 sensors. Then we will move to the main topic for today which is the symptoms of bad O2 sensor Chevy and understand more about the different symptoms that are present. After that, we will cover how to test O2 sensor with multimeter and lastly the oxygen sensor price. So, if you want to learn more, follow along.

What’s O2 Sensor

What’s an O2 sensor? Well, an O2 sensor also known as the lambda sensor is an automotive sensor that is designed to measure the flow of oxygen inside the exhaust.

The O2 sensor in simple words acts as a probe. This probe is connected to the PCM from one side and the sensing element from the other.

So, the sensing element of the O2 sensor is exposed to the heat created inside of the exhaust and here it measures the flow of oxygen.

This is quite an essential process because these sensors are helping the engine to adjust the air-to-fuel ratio, as well as help the catalytic converter do its job right.

Each car has at least two of these sensors. More on the types we are going to elaborate on later when we are going to discuss the upstream and downstream sensors. Now let’s see how the O2 sensor works before we dive into the symptoms of bad O2 sensor Chevy.

How O2 Sensor Works

Since we learned what is an O2 sensor, now let’s take a look at how this O2 sensor works in reality. What makes the O2 sensor special and an irreplaceable component in every modern automobile?

Well, this component is extremely crucial. Without this sensor, the engine will be practically unusable and will create a ton of symptoms of bad O2 sensor Chevy that we are going to discuss later on in the article.

The O2 sensor is bolted to the exhaust. And inside the exhaust, the probe is monitoring the flow of oxygen.

This oxygen monitoring is really essential because the air-to-fuel ratio has to be adjusted in the right manner.

The ideal A/F ratio is 14.7:1. And that is 14.7 parts of air per 1 part of fuel. And if the sensor is not there to read the gases, you could end up with a rich air-to-fuel mixture or a lean air-to-fuel mixture.

A rich air-to-fuel mixture is a state where you have too much fuel and too little air. While the lean air-to-fuel mixture is the situation when you have too much air and too little fuel.

Usually, when the O2 sensor goes bad, there is a rich state. When you have too much fuel and too little air in the system. And the fuel is not able to burn.

Another thing to add is if the sensor after the catalytic converter is broken, you will end up with a check engine light, and also the work of the catalytic converter will be not good since the sensor is not monitoring the flow of gases after the catalytic converter.

What O2 Sensor Is Upstream

The upstream is the sensor located before the catalytic converter. Thus the name upstream. If you didn’t know, the exhaust is usually routed downwards.

So, one of the sensors is located before the catalytic converter and this sensor is called upstream sensor. The name is really self-explanatory.

What is interesting about this sensor is that this sensor is dedicated to keeping the air-to-fuel ratio. This means that it adjusts the air-to-fuel ratio inside of the engine and makes sure that the engine works perfectly well. Else, it will create symptoms of bad O2 sensor Chevy and you will face a ton of issues. More about the symptoms, we are going to elaborate on later in the article.

What O2 Sensor Is Downstream

The sensor located after the catalytic converter is called a downstream sensor. So, before the catalytic converter is the upstream O2 sensor after the catalytic converter is the downstream O2 sensor.

What is worth noting is that these two sensors are not interchangeable. This means that the O2 sensor before and after the catalytic converter is not the same.

The downstream sensor has a different purpose. Its purpose is to make sure that the catalytic converter is working properly. And honestly, when this sensor goes bad is not always such a big deal as the upstream sensor. The upstream sensor is far more sensitive to creating symptoms of bad O2 sensor Chevy.

Symptoms Of Bad O2 Sensor Chevy Silverado

Now let’s move to the main topic and discuss more about the symptoms of bad O2 sensor Chevy Cruze and learn all about them.

Knowing the faulty oxygen sensor symptoms is really crucial when it comes to solving this problem. Because without you knowing them well, you could make a wrong call and replace something else on the car and spend a ton of money on parts that didn’t need changing. This is why we are going to cover the most common symptoms, so you get a better perspective of what to expect.

1. Check Engine Light – Symptoms Of Bad O2 Sensor Chevy

The first symptom in our list of symptoms of bad O2 sensor Chevy is the check engine light. So, what does this check engine light mean?

Well, the check engine light is an indication of a problem. This means that your car has some issues and needs to be properly diagnosed.

So, you need to attach an OBD2 scanner and let the scanner scan the vehicle for issues. If between the codes there are codes that are associated with some of the O2 sensors, then you get a clear idea of what could be the issue with the vehicle and move on to diagnosing that specific sensor. Example codes are P0150, and P0140 code Chevy.

There are a lot more depending on the sensor. But usually, they are in this range. Now let’s move on with the other symptoms of bad O2 sensor Chevy.

2. Rough Idle

The next in our list of symptoms of bad O2 sensor Chevy is the rough engine idle. Rough idle will be present when the car has a problem with the upstream O2 sensor since this sensor is dedicated to adjusting the air-to-fuel ratio.

If you notice something like weird engine work and the engine doesn’t idle as it should. Then you should check some components like the spark plugs, coils, MAF, MAP, and also the O2 sensor. These are the most common causes of these problems.

If the O2 sensor is the one to blame, replace it and you will be good to go. Just make sure that you diagnose the correct one.

3. Drop In Fuel Economy – Symptoms Of Bad O2 Sensor Chevy

Now let’s move on to the next symptom in our list of symptoms of bad O2 sensor Chevy. And this is the symptom when you start to feel a big drop in your fuel economy. So, why is this the case?

Well, this is the case because when the upstream O2 sensor fails, you will not have an engine that has a good air-to-fuel ratio.

The air-to-fuel ratio could be extremely rich. And when you have a rich air-to-fuel mixture, you also have a big drop in fuel economy and a ton of money spent on gas.

So, whenever you have an instance like this when you have a big drop in fuel economy, it is really important to make sure that this is not caused by some problems with the O2 sensor.

Usually, bank 1 sensor 1 and bank 2 sensor 1 are the ones that do all these problems and cause very big headaches to car owners. Now let’s move on to the next symptoms of bad O2 sensor Chevy Silverado.

4. Drop In Performance

The next in our list of symptoms of bad O2 sensor Chevy is the significant drop in performance. As you probably know, whenever the upstream sensor which is known as the air to fuel mixture sensor fails, it could trigger a significant drop in performance.

The fuel consumption will really increase and the car will run rich. While the performance will drop. You will feel like you have lost 30 horsepower or more.

The engine will be really slow to respond. No matter how hard you press on the throttle, the rich air mixture will do its thing and you will struggle for performance.

So, whenever you notice something like this and there is a significant performance loss, it is important to act quickly and sort out the problem before the problem becomes too big and eventually damages the catalytic converter.

And trust me, a rich air-to-fuel mixture can damage the catalytic converter and basically ruin it from the inside. So, you definitely don’t want to pay for an expensive catalytic converter replacement. Now let’s move on to the next symptoms of bad O2 sensor Chevy.

5. Emissions Test Failure – Symptoms Of Bad O2 Sensor Chevy

Next on our list of symptoms of a bad O2 sensor Chevy Cruze is the emissions test failure. Let’s say that you live in a state like California or New York where they are pretty strict with the emissions.

You will take your car to test and you will probably fail if the O2 sensor is bad. The readings from your car will not match with the recommended values and your car will fail.

They will probably return you home to fix the problem and bring the car again for testing. This can be rather frustrating if you are asking me because you separated a whole day specifically for this and you are failing the test.

Not an ideal situation. But that’s how things go. So, it is important to detect problems like this with the O2 sensor on time. As well as fix them on time to avoid a frustrating situation like in this case. Now let’s continue with our symptoms of bad O2 sensor Chevy Trailblazer.

6. Black Smoke From The Exhaust

Now let’s move on to the next symptoms of bad O2 sensor Chevy Silverado. And the next symptom on our list is the black smoke from the exhaust. So, why is this the case?

Well, this is the case because the car is not able to adjust the air-to-fuel mixture correctly. And it runs pretty rich on gas. So, when there is too much gas in the mix, the car engine will simply produce more emissions and also this will resemble black smoke that will be released from the exhaust pipe.

Whenever you notice something like this is to make sure that this is not because of an oil-burning issue. Usually, cars that burn oil release black smoke while they are revving high. While in the case of the O2 sensor this smoke is constant. And also, the smell is the most important. And that’s what we are going to cover in the following chapter.

7. Strong Gas Smell From The Exhaust

And the next symptom in our list of symptoms of a bad O2 sensor Chevy is the situation when you experience a strong gas smell.

Along with the black smoke from the exhaust, there will also be some strong odor of gasoline coming from the exhaust pipe. So, why is this the case?

Well, this problem will be a direct consequence of the problem with the bad air-to-fuel mixture caused by the bad O2 sensor.

More precisely, a rich air-to-fuel mixture will cause the car to run extremely rich and will burn a lot of gas. So, some of this gas will be released unburnt and there will be a really strong odor of gasoline when the car is running.

So, if you notice this symptom. Then you know that you definitely have a problem with the O2 sensor and then you will need to test the specific sensor. But how you can do that? More about this topic we are going to elaborate in the following chapter, where we are going to explain how to test O2 sensor with multimeter. So, you definitely don’t want to miss that.

How To Test O2 Sensor With Multimeter

So, we covered the symptoms of bad O2 sensor Chevy and learned quite a bit about them. So, how can you test an O2 sensor with a multimeter?

Well, before you do this, you first need to make sure that this problem is caused by the O2 sensor itself. So, grab an OBD2 scanner and scan the car for codes. If one of the sensors is faulty, you will probably receive a code concerning this specific censor.

Depending on the car that you have, there could be bank 1 sensor 1, bank 1 sensor 2, bank 2 sensor 1, and bank 2 sensor 2.

Nevertheless, the testing of the sensor can be done with a multimeter and a little bit of heat. So, you will need to tweak the multimeter to measure volts. Then apply heat on the probe of the sensor with a blow torch and if the sensor is producing a voltage in the factory recommended spec, you have a good sensor. If the sensor produces abnormal readings or no readings, then you have a bad O2 sensor that has to be replaced. How it is done you can check in the video below.

There is also another method where you can bench test the sensor without a blow torch. For this, you will only need to measure the resistance of the O2 sensor. By doing this you will see if there is resistance or an open loop. In the next video, you have the exact timestamp on the test. Also, there is another method done in the video at 7:20 where he back probes the connectors to see if there is a connector wire.

Oxygen Sensor Price

Now since we cleared the symptoms of bad O2 sensor and learned about the diagnostics process and how it is done with a multimeter. Let’s now cover the costs involved in replacing the sensor.

A replacement sensor is anywhere between $150 to $350 depending on the make and model. The best is to go for an OEM sensor and not for a cheap one. This is the case because a lot of these cheap sensors don’t work at all sometimes or work with problems. So, better to pay a bit more and get the thing you need than get another problem. That’s our two cents on this topic.

Conclusion To Symptoms Of Bad O2 Sensor Chevy

In this article, we have covered quite a bit when it comes to O2 sensors. First, we learned a lot about car diagnostics and how it is done. Next, we covered interesting facts about the O2 sensor and its function.

Then we moved on to the symptoms of bad O2 sensor Chevy and learned all about the symptoms concerning this component. Then we learned how you can diagnose one with a multimeter as well as the cost involved in buying one.