What Is The Emission System Problem Honda Accord?

The issue with the emission system Honda Accord is a serious problem that every vehicle owner should be aware of. A Honda Accord’s emission system is critical in controlling the release of harmful gases into the environment and ensuring compliance with environmental standards. When the Honda Accord 2021 emissions system problem or even the 2018 Honda Accord emissions system problem occurs, a warning light appears on the dashboard.

This is more than just a warning light; it can indicate serious underlying issues that affect both the vehicle’s performance and its environmental impact. Any Honda Accord owner must understand the causes and solutions to the Honda Accord emissions system problem.

What Is The Emission System Problem Honda Accord?

If your check emissions light comes on, you could be facing an emission system problem Honda Accord. This problem can range from a minor vacuum leak to significant problems with your catalytic converter. Learn more about these issues and get the necessary help before it’s too late.

Causes Of Emission System Problem Honda Accord

The Emission System Problem Honda Accord is a complex assembly of parts that ensures harmful gases are treated before being released into the environment. When something goes wrong in this system, your car will warn you with an emission system warning light. Here’s a look at some common causes of emission system problem Honda Accord and the potential solutions:

Faulty Mass Airflow Sensor


The mass airflow sensor monitors oxygen levels in your exhaust. A malfunctioning or clogged sensor can cause increased fuel consumption, challenges in starting the engine, and other issues.


You may clean the sensor using electrical contact cleaner and cotton swabs. If cleaning does not resolve the issue, consider replacing the sensor. Replacing a Honda Accord mass airflow sensor might cost between $250 and $450.

Failing Fuel Injectors


If fuel injectors become blocked or leak, it can lead to similar symptoms as a faulty mass airflow sensor, including a strong gas smell.


Fuel injectors can be complex to handle; it’s best to have them diagnosed and replaced by professionals. Ignoring this issue could result in the engine locking up.

Damaged Catalytic Converter


The catalytic converter plays a crucial role in converting harmful gases into environmentally friendly ones. When it starts to fail, it will trigger the emission system warning light.


Replacing the catalytic converter is the only option here. It may cost around $1,500 plus labor, so it’s best to have it replaced at the dealership to ensure the use of high-quality parts.

Dirty Air Filter


If the air filter becomes clogged with dirt, it will restrict airflow to the engine, leading to an emission system warning.


Consider cleaning or replacing the air filter. Replacement is often the best option, costing around $150 for parts and labor.

Issues Specific To Honda Accord Models


Certain models may have specific problems, like emissions system problem honda accord 2021, 2018 Honda accord emissions system problem, etc.


Refer to your specific model’s manual or consult with a professional mechanic familiar with your particular Honda Accord variant.

What Does It Mean When Your Car Says Emissions System Problem?

When your car displays the warning “emissions system problem,” it’s a clear indication that something in the vehicle’s emissions control system isn’t working properly. This system is intended to limit the amount of pollution released into the atmosphere, and any problems with it can result in increased emissions. Understanding what this warning means is critical to maintaining your vehicle’s performance as well as compliance with environmental regulations. Here’s what you should know:

O2 Sensor Malfunction

The O2 sensor helps manage the fuel mixture within the engine. If this sensor fails, it can lead to improper fuel mixing, causing increased emissions and potentially triggering the “emissions system problem” warning.

Faulty Catalytic Converter

The catalytic converter is responsible for converting harmful gases into less harmful ones. A failure here can lead to higher levels of pollutants being released into the atmosphere.

Vacuum System Issues

The vacuum system in a Honda Accord can perform various tasks, including reducing harmful emissions by routing exhaust fumes through the engine. A problem within this system can be one reason behind the “emissions system problem” warning.

Mass Air Flow Sensor Problems

A problem with the mass air flow sensor, particularly in models like the 2018 honda accord emissions system problem, could lead to this warning. This sensor helps in maintaining the correct fuel-to-air ratio within the engine, ensuring efficient combustion.

Problems With Fuel Injectors

Dirty or failing fuel injectors might lead to the emissions system problem warning. They can cause a host of issues, including increased fuel consumption, difficulty in starting the engine, and higher emissions.

Leakage In The System

Any leaks within the emissions system, from the exhaust manifold to the various connecting hoses, can cause this warning to appear. These leaks may result in harmful gases escaping into the atmosphere directly.

Can You Drive With The Emission Control System Light On?

The emission control system light illuminates on your dashboard as an essential alert to notify you that there might be a problem within your vehicle’s emissions system. This warning should not be taken lightly, as it signals a potential issue with components designed to minimize harmful emissions. Here’s what you need to understand about driving with the emission control system light on:

Immediate Attention Required

If the emission control system light comes on, it’s an immediate indication that you need to check your vehicle. Although driving a short distance to a service center might be necessary, prolonged driving with this light on could lead to more serious problems.

Potential Performance Issues

Ignoring the light might result in decreased performance or fuel economy in your vehicle, including problems specific to certain models like emissions system problem honda accord 2021. Continuing to drive without addressing the problem can cause further damage to other parts of the vehicle.

Legal Considerations

Driving with the emission control system light on may lead to non-compliance with emission regulations in some jurisdictions. This can result in fines or penalties, as your vehicle might be releasing pollutants above the legal limit.

Safety Concerns

While the light itself doesn’t directly correlate with vehicle safety, the underlying issues causing the light to turn on might affect the overall functionality and safety of the car. Ignoring it might lead to other problems that could pose safety risks.

Possible Causes

The light could indicate a range of issues, from a simple vacuum leak or sensor failure to more serious concerns like a failing catalytic converter. Understanding the specific cause requires professional diagnosis.

Emergency Headlight Usage

The section also mentioned turning off headlights and taillights if not using the emission control system. While the connection between emission control and headlight usage might not be direct, it’s essential to comply with all traffic regulations, including proper headlight usage, to ensure safety on the road.

Cost Of Catalytic Converter And Emission Control System Repairs

Catalytic Converter Honda Accord: If your vehicle has over 100,000 miles, consider replacing the catalytic converter, costing between $2,027 and $2,092.

Emission Control System Repairs: Repairing an emission control system may vary in cost from around $175 to $500.

Why Is My Honda Accord Check Engine Light On?

The question “Why does my Honda Accord check engine light on?” is one that many Honda owners find themselves asking at some point. The check engine light in your Honda Accord can indicate a variety of potential problems, and it’s essential to understand the underlying issues to address them appropriately.

Sensors Failure

Honda Accord engines are equipped with multiple sensors. Failure in any of these, such as the mass air flow sensor or an O2 sensor, can cause the check engine light to illuminate. Dirty air filters or clogged mass airflow sensors are common causes for sensor failure.

Vacuum Leaks

Any vacuum leaks within the engine can also lead to the check engine light coming on. The vacuum system in the Honda Accord plays a crucial role in reducing harmful emissions, and even a small leak can result in significant problems.

Catalytic Converter Problems

Issues with the catalytic converter can cause the check engine light to come on. The converter is vital for converting harmful gases into environmentally friendly ones, and its failure can lead to higher emissions.

Engine Oil System Leakage

If there are signs of leakage in the engine oil system, it may indicate the need for a new head gasket, causing the check engine light to activate.

Spark Plug Issues

Spark plugs play a crucial role in the ignition system, and their failure can lead to the check engine light coming on. Regular inspection and replacement of spark plugs based on testing results can prevent this problem.

Emissions System Problems

Problems related to the emissions system problem honda accord can lead to the check engine light illuminating. It can range from small vacuum leaks to significant issues with components like the catalytic converter.

2018 Honda Accord Emissions System Problem

Specifically, in the 2018 Honda Accord model, the check engine light may turn on due to problems with the mass air flow sensor. Ensuring the wiring is in good working order is essential to fix this issue.

Emissions System Problem Honda Accord 2021

In the 2021 model, reduced engine performance or lowered engine temperature due to emissions system problems may also result in the check engine light coming on.


Can A Dirty Air Filter Cause The Emission System Problem Honda Accord?

Yes, a clogged air filter can restrict airflow, causing emission system warnings.

How Much Does It Cost To Fix The 2018 Honda Accord Emissions System Problem?

Costs vary depending on the issue, ranging from $175 to $2,092.

Can I Drive With The Emission Control System Light On?

It’s essential to address the issue promptly, as driving without the emission control system light may lead to penalties.


Understanding the emission system problem Honda Accord is vital for proper maintenance and care. Whether it’s a 2018 Honda Accord emissions system problem or an issue with a newer model, addressing it promptly ensures optimal performance and adherence to environmental standards. Always consult a professional mechanic to diagnose and rectify these issues, keeping your Honda Accord in peak condition.

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Ammar Masoud

I have had a long and fulfilling career in the automotive industry, primarily with Honda and Acura. With 15 years of experience as a Honda service technician, I became highly skilled in repair and maintenance, gaining a deep understanding of these vehicles. After many years in the automotive field, I decided to embark on a second career in industrial manufacturing. It was a significant change, but I found that the skills I had honed in the automotive industry were incredibly valuable in my new role. In my current position in industrial manufacturing, the demand for quality workmanship and meticulous attention to detail is paramount. Fortunately, these are traits that I have cultivated throughout my years in the automotive industry. I take pride in applying these skills to meet the high standards expected in the manufacturing sector.