"Emission System Problem, Power May Be Reduced" Honda Accord. What's This?

You've just bought your brand-new Honda Accord, and after driving a few miles, the warning light, "Emission System Problem, Power May Be Reduced," comes on. This can leave you reeling in shock since you don't expect a new car to have issues.

Emission system problem message highlights

• Common reasons:catalytic converter problems, oxygen sensor faulty, issues with fuel combustion
• How to fix:read the codes, inspect the emission system units
• Possible consequences:you won't pass the fog test
• Priority level:High
• Can you drive?Yes
• DIY repair:Impossible
• Repair price range:$300-$1,500

What Does the "Emission System Problem, Power May be Reduced" Mean?

When the warning light indicating an emission system problem comes on in the dashboard of your Honda Accord, it's usually a sign of an imbalance of fuel-to-air ratio in the engine. This can be caused by various reasons, which we'll look at later.

Any issue that affects the engine emission system triggers the powertrain control module to log a fault. This consequently leads to the warning light coming on. The emissions system light and other warning lights, such as the transmission warning light, can accompany the check engine light.

The warning lights show cryptic symbols and may be hard to interpret hence the need for a diagnostic scanner tool to read the diagnostic trouble codes. This will give you a better clue on the issue. 

What are the symptoms of an Emission System Problem?

One of the tell-tale signs of a problem with the emission control system is that the check engine light comes on in conjunction with the emission system warning light. The vehicle may then shift into limp mode or safe mode.

Limp mode is a common security feature in a car that is activated when the transmission control unit detects an issue. What results is that the engine loses a lot of its power, and the car's acceleration is greatly reduced. This prompts the vehicle to only move at a speed not exceeding 40 miles per hour. That impairs drivability, especially on highways. 

The car goes into safe mode to reduce the emission of harmful pollutant gases into the atmosphere. The vehicle stays in safe mode until the diagnostic trouble code is read and the issue causing the emissions problem is fixed.

Other symptoms of emissions system problems are: 

• An increase in fuel consumption.
• A rough engine idling and running.
• Trouble starting the engine.
• Stalling and hesitating.
• Engine misfires.
• Fluctuation of the RPM needle.
• A loss in fuel mileage.
• An engine drag.

Can You Drive your Honda Accord with the Emission System Warning Displayed?

When the emission system warning light illuminates the dashboard of your Honda Accord but doesn't blink or flash on or off, it means it doesn't need immediate attention. This means you can drive safely to your destination except when driving on highways once the limp mode is activated.

However, you'll need to have your car inspected as soon as possible to avoid aggravating the issue. Ignoring the issue may lead you to costly repairs down the road such as blowing the turbocharger when the catalytic converter is clogged. 

The emission system warning light blinking on and off in your dashboard is a different ball of wax. It's a sign that the problem is severe and your car needs immediate attention. This also means drivability may be affected and unsafe to drive.

A problem with the emission system could also get you ticketed by the police in some states since it's a cause for the emission of a lot of harmful gases such as hydrocarbons, carbon monoxide, volatile organic compounds, nitrogen oxides, and sulfur dioxide into the environment.

What are the Causes of the Emission System Problem in the Honda Accord?

Causes of the emission system problem may range from a small issue, such as a loose gas cap, to a complicated case, such as a faulty catalytic converter which is more costly and outside the scope of do-it-yourself home mechanics. Below are common causes of emission system issues that could be causing the warning light on your Honda Accord to come on:

1) Loose Gas Cap 

The emission system warning light could come on because of an issue as simple as an improperly sealed gas cap. A loose gas cap can lead to an EVAP system leak where the fuel vapors escape from the gas tank. Entry of dirt and grime into the fuel tank through a non-secure gas cap can lead to contamination of the fuel injectors. If the car's computer detects leaks, it'll set off the check engine light. 

2) Malfunctioned Oxygen Sensors

A bad oxygen sensor can cause the emission light to come on. The work of the sensor is to measure the amount of unburned oxygen in the exhaust fumes as they exit the engine. It then relays the information to the engine control module which then acts accordingly. If too much oxygen exists in the exhaust system, it makes the fuel burn more quickly.

This lowers the miles per gallon and can damage the spark plugs and the catalytic converter. A faulty oxygen sensor can also lead to the emission of more harmful pollutants from the exhaust system.

3) A Failing Mass Airflow Sensor

A mass air flow sensor(MAF sensor) is a crucial component in the electronic fuel injection system. It's also referred to as an air meter. Its function is to measure the mass flow rate of air entering the fuel-injected internal combustion engine.

It then sends this information to the Engine Control Unit, which then uses it to determine the right amount of fuel the car needs for the optimum air-fuel ratio. Dirt or debris can clog the MAF sensor and cause damage, making it not monitor the correct amount of air entering the engine. The symptoms of a failing MAF sensor are jerking, stalling, or hesitation when the vehicle is accelerating.

Your Honda Accord may also run rich, meaning that the air-fuel ratio is too rich, or run lean, where the air-fuel ratio becomes too lean. These symptoms are the same as those of damaged spark plugs or fuel injectors; therefore, trying to get the right diagnosis can be confusing. 

4) Faulty Fuel Injector or High-Pressure Fuel Pump

Although a faulty fuel injector is a common problem affecting the Emission system in the third generation of Honda Pilot, it can also cause an emission system problem in the Honda Accord, though not as common.

The fuel injector mirrors a spray nozzle by breaking up fuel into a fine spray in the engine combustion chamber. Carbon buildup may cause the fuel injector to clog, making it unresponsive. The injector may also become faulty due to leakage of fuel. A strong smell of fuel in the cabin is a symptom of a leaking fuel injector that needs fixing.

5) A clogged Air Filter

Dirt and debris may also clog the air filter, malfunctioning and triggering the ECU to make the emission system problem warning light come on. An air filter's job is to prevent any dirt, particles, debris, or insects from entering the engine and ensure a proper mix of fuel and air for optimum engine performance. Some of the symptoms of restricted airflow due to a clogged air filter are:

• Odd engine noises coming from the engine bay.
• Black smoke coming from the exhaust.
• A weak fuel economy.
• Poor engine performance.
• Check engine light coming on.

6) Vacuum Leak

A vacuum leak can also be one of the causes of the problem with the emission system warning light illuminating your Honda Accord's dashboard. The vacuum pressure provides power to some car components, such as the power steering pump. A vacuum leak can make steering harder. The vacuum system also helps reduce harmful emissions from the car. It does this by directing the fumes obtained from the evaporation of gasoline throughout the engine. The vacuum leak can be caused by cracking or drying out of vacuum hose pipes over time.

This can be due to exposure to high heat or cold temperatures. Symptoms of a vacuum leak include a high idle RPM, engine stalling or hesitation, and a hissing or sucking sound.

7) A Malfunctioned Catalytic Converter

The catalytic converter is part of the exhaust system, and its malfunctioning can cause an issue with the emission system. Its main function is to convert harmful gases such as hydrocarbons and carbon monoxide into less toxic products, including carbon dioxide and water before they exit from the exhaust system.

When the catalytic converter is not functioning properly, there's a buildup of toxic gases, which affects the emission system and allows the release of harmful gases into the environment. 

How to Fix the Problem with Emission System Alert on a Honda Accord

For the problem with the emission system warning light to go off, one has to make the correct diagnosis of the issue, fix the issue, and remove the present diagnostic trouble code using a diagnostic tool. Below are some ways you can fix the problems of the emission system.

• The first step is to make the right diagnosis with the help of a diagnostic tool, such as an OBD II diagnostic tool. You can use it to read the code in the ECU. Getting the diagnostic trouble code gives you a better idea of what the problem could be to help fix or replace the right car part.
• First, you should check the easiest part to fix: the gas cap. Ensure the gas cap is well tightened by twisting it clockwise until you hear a click. The click signals that it's properly closed. You can turn it until you hear a double click for good measure. Some newer models of Honda don't have a gas cap but, instead, have flaps in their place. If the flaps are not well positioned, insert your finger into the gas hole and adjust the flaps. After the fixing, it takes driving a few miles for the warning light to go off.
• If it's an issue with the MAF or the oxygen sensors, your best bet would be to replace the sensors for the emission system warning light to go off. Replacing the sensors is relatively easy and can be done by experienced DIYers. Another option would be to clean the sensors using cotton swabs and electrical contact cleaner. Ensure the cleaner dries before reinstalling the sensor.
• If it's an issue with the vacuum leak, replace the vacuum leak hose pipes to correct the problem.
• If it's an issue with the fuel injector, it can either be repaired, cleaned, or replaced. Fixing the fuel injectors can be hard even for experienced DIYers; therefore should be left to trained professionals to diagnose and handle the issue.
• An issue with the catalytic converter can be frustrating since it's costly to replace. The ballpark estimate for replacing a catalytic converter is $1500. And that's without paying for labor. Pretty high, right? Most car owners with the issue opt to sell their cars. If you decide to replace the catalytic converter, your best option would be to do it at the dealership to ensure original equipment manufacturer (OEM) parts are used.
• Other less common problems, such as leakage in the exhaust manifold or the exhaust gas recirculation, can also be diagnosed and fixed.
• After getting the correct diagnosis and fixing the problem, remember to reset the Honda Accord emission system check alert through a scanning device once the issue is fixed. In some cases, you'll have to drive a few miles before the warning light, and the DTC code can clear.

Bottom Line

There you have it-what the Emission System Problem, Power May Be Reduced" warning light means and how to fix it. Ensure you assess the issue and its fixes and determine if you can fix on your own or leave it to qualified Auto mechanics to handle it.