How To Replace The Oxygen Sensor To Fix The P0171 Trouble Code

Replacing a faulty oxygen sensor that is causing the P0171 trouble codeOpens in a new tab.

Just follow this step-by-step guide and at the end of it, you will know how to replace the oxygen sensor and fix the P0171 trouble code.

What Is The Purpose of The Oxygen Sensor

The purpose of the oxygen sensor in a car is to measure the amount of unburned oxygen in the exhaust system.

This information is then used to adjust the fuel mix and ensure that the engine runs at maximum efficiency.

The oxygen sensor works by measuring the difference between two different types of gases, which are usually air and exhaust gas.

When these gases come into contact with the oxygen sensor, it produces an electric current that can be used to determine how much fuel needs to be injected into the engine.

The result is a more efficient combustion process and reduce emissions from your vehicle’s exhaust system.

By using this technology, manufacturers can build engines that run cleaner, use less fuel, and produce fewer harmful pollutants in our atmosphere.

The Role of The Oxygen Sensor In The P0171 Trouble Code

The oxygen sensor plays an important role in the P0171 trouble code.

The oxygen sensor is responsible for detecting the amount of oxygen in the exhaust system and relaying this information to the engine control unit (ECU).

When there is too much oxygen in the exhaust, it indicates that the air-fuel mixture is running lean and needs to be adjusted.

If this condition persists, it can lead to poor performance, increased emissions, and even damage to other components of your vehicle’s engine.

How To Replace The Oxygen Sensor To Fix The P0171 Trouble Code

How To Replace The Oxygen Sensor To Fix The P0171 Trouble Code

The oxygen sensor also referred to as the air-fuel ratio sensor can trigger a P0171 trouble code if it becomes faulty.

Here is how to replace the oxygen sensor to fix the P0171 trouble code in your vehicle:

1. Order a new oxygen sensor

New oxygen sensor cost between $35-$80. When it comes to choosing between low-quality or high-quality oxygen sensors, I always opt for the more expensive one.

I mean, it is only $80 but you will save so much money down the road because your car will start to burn the proper amount of fuel.

Get a new oxygen sensor from amazon.comOpens in a new tab.

2. Scan the vehicle for trouble codes

Scan your vehicle using an OBD2 scanner to verify that you have a P0171 trouble code.

To do so, connect the OBD2 scanner to your vehicle’s port and scan it for all pending and stored trouble codes.

If your oxygen sensor is indeed faulty and is the cause of a lean condition, you will see a P0171 trouble code.

3. Locate the faulty oxygen sensor

The oxygen sensor is located on the exhaust manifold, but you can always refer to your owner’s manual to find the exact location.

With the engine cold, try to locate the exhaust manifold. Remove any plastic covers that may be in your way of locating the oxygen sensor.

4. Remove the old oxygen sensor

There is a special tool designed to remove the oxygen sensor without damaging the cable.

I got mine on amazon.comOpens in a new tab.

Basically, it is a 7/8 inches socket that has an opening where you can put the cable from the oxygen sensor and remove it without tearing anything up.

Disconnect the electrical connector first.

Remove the old oxygen sensor and inspect the exhaust manifold housing.

5. Install the new oxygen sensor

Using the same oxygen sensor tool, install the new oxygen sensor.

Make sure to tighten the oxygen sensor nicely before connecting the electrical socket.

Once everything is in place, connect the electrical socket.

6. Erase the stored P0171 trouble code

How To Replace The Oxygen Sensor To Fix The P0171 Trouble Code

Using an OBD2 scanner, you need to erase the stored P0171 trouble code so that the check engine light can go off.

If you are not sure how to do that, you can check out How To Reset The P0171 Trouble Code After Repair In Under 5 MinutesOpens in a new tab.

In Conclusion

Replacing the faulty oxygen sensor that has been causing the P0171 trouble code is an easy job that can cost you between $30 and $80 for the part itself.

It will cost a lot more than that if you go to the mechanic shop.

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Igor Iwanowski

I am a certified Automotive Service Excellence (ASE) mechanic since 2018. I specialize in Brake systems, dashboard warning lights, EGRs, general engine problems, EVAP and Emissions issues.

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