How to Fix Code P2198: Common Causes and Solutions

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Car trouble doesn't happen often, but when it does, you need to know what's going on and how to fix it. How many of these error codes have you come across? P0299, P0021, or even P0218? How about the elusive code P2198? 

The good news is that we're here to help! In this article, we'll walk through all the common causes for a car giving off an error code P2198, as well as some ways you can solve the problem. Read on for more information!

What is Code P2198?

The vehicle's primary computer or PCM uses input from different sensors to get the optimal air-fuel ratio. One sensor that provides essential data to the PCM is the oxygen sensor. The oxygen sensor monitors the amount of air in the engine to determine if it is running in a rich or lean condition. 

If the oxygen sensor detects excessive air to fuel ratio of the exhaust on bank 2, this causes the code P2198 to appear when you check it using your OBD2 tool. This ratio is relayed to the ECM, which uses it along with comparisons to the outside air to manage the engine's air-to-fuel ratio. 

This DTC code indicates too much fuel concerning the oxygen in your car. Or probably the oxygen sensor is faulty and reading an incorrect air/fuel ratio.

Causes of Code P2198

There are various reasons why this code may come up on your vehicle. Some of the common causes include:

  • Faulty oxygen sensor (sensor either has a short or is not working at all)
  • The mixture air/fuel ratio is too lean due to incorrect spark plugs, ignition wires, and distributor cap & rotor
  • An open or loose electrical wire connection in the mixture air/fuel ratio sensor circuit
  • Faulty PCM (the engine control module)

How to Fix Code P2198

Now that you know the symptoms, how do you fix them? If you are unsure how to fix code P2198, take your vehicle to a mechanic or auto parts store. A professional will diagnose the problem quickly and how much it would cost for any repairs. However, if you are confident enough to fix it yourself, you may rely on these steps.

As the P2198 code is generic for various vehicle brands, this repair step guide may work for you. However, this code causes a variety of reasons. It will help if you identify first what your car's problem is.

A vacuum leak is the most common problem for this code. If this is your car's problem, it is easy to fix, and you can do it by yourself. Let's take a look closer at how to fix this issue.

What You’ll Need:

Step-by-Step Guide

  • Find the source of the leak by using a water bottle. When your car is running, pour the bottle around the suspected area and listen for hissing sounds. If there are any leaking areas, they will be easy to identify by that sound.
  • Once the vacuum leak is located, use duct tape to seal it off.
  • Test drive your vehicle and check if the code goes away using your OBD tool scanner.
  • You have successfully solved the problem if the code does not appear after the test drive.
  • If the code appears again after some time, the leak has resurfaced, and you must repeat these steps.

Since code P2198 is not just a vacuum leak, don't wonder if repairing your vacuum will not address the issue. It is more likely that you are dealing with a faulty oxygen sensor. In such a case, replacing the oxygen sensor is the best solution.

How to Replace the Faulty Oxygen Sensor

Replacing the faulty oxygen sensor may sound easy, but you will need to find the right part for your specific vehicle. You can start the replacement process after having a suitable oxygen sensor for your car.

  • Remove the old oxygen sensor from your vehicle using a socket. Make sure to buy an oxygen sensor that is identical to the old one.
  • Put the anti-seize cream on the thread from the new oxygen sensor package. You don't have to put all the anti-seize cream; a small amount will do. Just make sure to cover the whole thread.
  • Thread it back to where you remove the old one. When turning the new oxygen sensor on, use a torque wrench, so it doesn't get damaged by being over-tightened or under-tightened.
  • Now that you have already had your new oxygen sensor start the car and let it idle until it warmed up to operating temperature, which is how long it should take.
  • Go for a drive and see how the vehicle is running. If it's still giving you the P2198 code, there might be other issues causing this problem, and you will need to bring your car to a mechanic to have it checked.

Symptoms of the P2198 Code

Before diagnosing your vehicle, you may probably notice some signs and symptoms. One of the most common is that your check engine light will be illuminated. You may also experience poor gas mileage and a decrease in engine performance. If you're lucky, your vehicle may only stall out once it reaches operating temperature. Worst case scenario would be a fire.

Common Mistakes When Diagnosing Code P2198

Others tend to conclude without ruling out other code causes when diagnosing this code. This causes mistakes and can cost you more money in the long run. Some of these mistakes are:

  • The code is caused by a bad oxygen sensor and replacing it without checking for other possible causes.
  • Not checking if the engine is getting enough fuel.
  • Jumping to conclusions and replacing parts unnecessarily.
  • Not checking if there is a vacuum leak.

Before jumping to the wrong conclusions, you must check all these possibilities. If you have found out all other causes and the code is still present, you can replace the oxygen sensor.

Code P2198 FAQ

1. Is code P2198 serious?

The code P2198 is not a serious code, and it will not cause any damage to the engine. However, it can indicate a problem that should be fixed as soon as possible.

2. Can I still drive with code P2198’s presence?

You can still drive with the code P2198 presence, but you should have the problem fixed as soon as possible.

3. How soon do I need to fix code P2198?

You need to fix this code as soon as possible. If you don't solve the problem, your car might not pass an emission test, and it will start showing other issues related to the more severe oxygen sensor.

4. When should I replace my oxygen sensor?

The exact time you have to change your oxygen sensor will depend on how often you drive your car and how severe the problem is. You should replace it when you start seeing symptoms like the check engine light coming on or if there are noticeable drops in fuel efficiency.

5. How much would it cost to replace the oxygen sensor?

Replacing your oxygen sensor can cost anywhere from $100 to $300. It's best to ask a mechanic before you go ahead and replace it to know how much money you need to budget for this repair.


A car can be a big investment, so it is essential to keep up with the maintenance. How do you know when to take your vehicle in for service? One way is by checking error codes. 

The code P2198 is not as severe as you think; however, If you're experiencing any of the symptoms listed above, it's best to perform diagnostics to be sure. Not only will this repair help improve your car's performance, but it will also save you from spending more in the long run by improving your fuel efficiency.