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Can an Exhaust Leak Cause a Check Engine Light? (Explained)

Updated: Jan 9

Exhaust leaks can cause a variety of problems for a vehicle, including reduced fuel efficiency, decreased performance, and even potentially dangerous situations.

One question that many car owners may have is can an exhaust leak cause a check engine light to come on. In this article, we will explore the answer to this question and delve into the various ways that an exhaust leak can impact a vehicle's performance and diagnostic systems.


Table of Contents:

check engine warning light on a car dashboard

What Is an Exhaust Leak?

An exhaust leak is a hole or crack in the exhaust system that allows gases to escape. The exhaust system is responsible for removing harmful gases produced by the engine, and it is designed to be airtight to prevent these gases from entering the cabin of the vehicle.

Exhaust leaks can occur at any point in the system, including the muffler, catalytic converter, or exhaust pipe.

What Is a Check Engine Light?

The check engine light is a warning light found in most modern vehicles. It is designed to alert the driver when the vehicle's engine or emission control system is experiencing a problem.

This warning light is typically located on the dashboard and is either a steady or flashing orange light, depending on the severity of the issue. When the check engine light comes on, it is important to have the vehicle checked by a mechanic as soon as possible to diagnose and repair the issue.

A check engine light can be triggered by a variety of problems, including faulty sensors, a malfunctioning catalytic converter, or an exhaust leak.

Can an Exhaust Leak Cause a Check Engine Light?

The check engine light is a warning light that indicates a problem with the vehicle's emissions system or powertrain. The engine control unit (ECU) constantly monitors the performance of the vehicle and can detect a variety of issues, including an exhaust leak.

Yes, an exhaust leak can cause a check engine light to come on. The oxygen sensors in the exhaust system will send incorrect data if there's an exhaust leak, this issue will trigger the check engine light to come on.

However, there are many causes of a check engine light other than an exhaust leak

How Does an Exhaust Leak Affect a Vehicle?

An exhaust leak can have several negative effects on a vehicle.

  • Reduce fuel efficiency: A leak in the exhaust system can reduce the efficiency of the exhaust system, which can lead to decreased fuel efficiency and performance.

  • Louder exhaust and engine: An exhaust leak can also cause the engine to run louder and produce a rumbling or whistling noise.

  • Reduced performance: In some cases, an exhaust leak can even cause the engine to run poorly, reduce performance, or can even cause misfiring or stalling.

There are many other signs of exhaust leaks you should be aware of, such as a stronger smell of fuel, increased vibrations and unusual noises and sounds.

It can also be dangerous or even illegal to drive with a leaking exhaust system due to increased harmful emissions that can enter into the cabin inside of the vehicle.

a car driving on the road with smoke coming out around it

How to Fix an Exhaust Leak

If an exhaust leak is causing problems with your vehicle, it is important to have it repaired as soon as possible. The first step is to find the exhaust leak, which can be done through a visual inspection (see how to find an exhaust leak here).

Once the location of the leak has been identified, it can typically be repaired by replacing the damaged part or sealing the leak with an exhaust leak repair product.

It is important to have an exhaust leak repaired to ensure that it is properly fixed and to avoid any further issues.


In conclusion, an exhaust leak can cause a variety of problems for a vehicle, including the potential for triggering the check engine light.

If you suspect that you have an exhaust leak, it is important to have it repaired as soon as possible to avoid further issues and ensure that your vehicle is operating at its best.


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