Common Sign and Symptoms of a Bad Egr Valve: How to Test, Fix, and Change

Every driver should enjoy driving an eco-friendly vehicle. The way to achieve this is to ensure your vehicle has a fully functional exhaust gas recirculation (EGR) valve in your vehicle’s EGR system. Driving around town with a faulty or damaged EGR valve can be dangerous to your vehicle, your health, and your environment. You need to continue reading this article to be aware of the symptoms of a bad EGR valve, so you will know when this component is failing in your vehicle.

The EGR valve manages the thermal and chemical inevitabilities of your vehicle’s engine while driving. It keeps the engine operating smoothly for a long period. If you are unaware your vehicle has a faulty EGR valve, it can cause you many problems. Two of the major benefits of having an EGR valve is to reduce the temperature of your engine’s cylinder and lower the emissions that get released through the exhaust.

In this article, we will take a look at the symptoms of a faulty EGR valve. Also, how to test, fix, and change a bad EGR valve in your vehicle, and after reading this, you should be able to handle any EGR valve issues all by yourself.

What are the symptoms of a bad failing EGR valve?

Various symptoms can signify a faulty component in your vehicle’s engine system. So you need to be very observant of the symptoms of a bad EGR valve if or when exhibited by or vehicle. These symptoms include:

how to clean egr valve

Rough Idle

Your vehicle might start to experience a rough idle; this means that your vehicle will start chugging or vibrating while idling. This will cause you to have a rough driving experience, and you may likely bounce-off from your driver’s seat a little bit. When your engine idles, you might also notice a misfire when holding the steering wheel. If you have a malfunctioning EGR valve, your vehicle is bound to undergo rough idling.

This also means that little or no gas will be entering your combustion chamber, which affects the operation of the vehicle’s engine. As long as your EGR valve fails to open or close, your engine won’t idle properly, which implies that there is not enough gas entering the vehicle’s internal combustion chamber. This is the reason why your vehicle will idle roughly.

Poor Acceleration

When your vehicle’s engine valve is clogged, making it unable to close or open, this will cause the exhaust gas to flow into the intake manifold of your vehicle before it is needed by the engine. This causes poor acceleration while driving. The excess air will produce a lean mixture in your combustion chamber, and without the correct atmospheric oxygen ratios, there will be less power in the combustion stroke.

Overheating Of Your Vehicle

A bad EGR valve can be responsible for your vehicle’s engine overheating. A clogged EGR valve will not prevent the release of nitrogen oxides into the atmosphere, so your engine might increase to dangerous levels of temperature. It will also leave unburned fuel in your exhaust, and this might cause a strong gasoline smell in your vehicle and reduce the efficiency level of your fuel or diesel. As the temperature gets to a very high point, it will finally lead to your engine knocking.

Low Engine Performance

Once the EGR valve in your EGR system gets faulty, the very first symptoms are reflected through the performance of your vehicle’s engine. You will start observing issues like reduction in your engine’s power and also in the effectiveness of your gasoline pedal. Another sign you might notice is an unbalanced air-fuel ratio, which will result in reduced fuel efficiency. This will force you to spend more money purchasing a large quantity of fuel or gas for your vehicle.

Your vehicle will also begin to stall, becoming very sluggish and noisy. All this will cause your vehicle to use up more fuel or diesel than normal, abandoning you to deal with the fuel economy. This can also be a result of a bad spark plug, which is caused by carbon buildup.

High Fuel Consumption

A damaged EGR valve is most likely to cause your vehicle’s engine to begin to use up a lot of fuel than normal. For instance, your vehicle is normally on the average fuel economy of 25 miles per gallon or 10 liters per 90 kilometers. If you have a faulty EGR valve, there will be an increase in the gallon per mile, causing you to allocate more money to fuel your vehicle.

The EGR valve is also designed to help increase the fuel mileage of your vehicle. Therefore, once the valve gets damaged, that function will no longer be in play, so you will have to increase your fuel expenditure. The EGR valve circulates your exhaust gas back to your vehicle’s engine while keeping the combustion chamber’s normal temperature.

So, if this valve stops functioning, the combustion chamber might get a very high temperature above normal, causing the release of nitrogen gases to the environment.

Engine Check Light Turns On

You need to always check your engine indicators while driving in case of any fault springs up in your engine. The engine check light will illuminate when there is a faulty in the EGR valve. This light will not turn on until your vehicle’s computer picks up a negative signal from your EGR valve or any other engine component. Anytime you see your engine check light on, carry out a thorough examination of your vehicle’s engine as soon as possible.

The EGR valve is designed to close and open, but If it fails to perform any of these. Your vehicle’s computer will detect an issue with your engine and illuminate the engine check light on the dashboard.

Strong Gas Fumes

Because of a bad EGR valve, your engine will use up more fuel or diesel than normal. There is a very high chance that there will be a release of fuel through the tailpipe of your vehicle’s exhaust system. This condition can cause your vehicle’s exhaust to produce fuel fumes. Irrespective of the location of your vehicle’s cabin, you will perceive a strong gas fume, which is irritating and bad health-wise. When this odor is constantly perceived, you should pay attention to your EGR valve.

Failure In Emission Test

Car owners in the US must carry-out emission tests in their vehicles. This ensures that the gas released into the environment by their vehicle is in no way a threat to lives and the environment. You will have to perform this test every six months, depending on the state you live in. This test will alert a lot of drivers to pay more attention to the condition of their vehicle’s EGR valve.

How to test your EGR valve?

It will save you money and time if you learn how to test the EGR valve of your vehicle properly. After long use of your vehicle’s engine, the exhaust gas recirculation (EGR) system of your vehicle can cause carbon particles to accumulate on the internal surface of the valve passages, vacuum hose leaks, or mechanic part problems.

Knowing how to test your EGR valve is amongst the auto-mobile DIY skill you should acquire. Ensure you carry out this process during the day or use an under-hood work light during dark hours. These steps will show you how to test the old vacuum type EGR valve and the new computer-operated EGR valve. This is quite easy to do:

There are two techniques you can use to test the EGR valve. Starting with the vacuum type EGR valve. Note if the diaphragm starts to leak, then obviously the valve is bad. You will have to replace it. The best way to test this valve is to purchase a vacuum tester. Not only that it is used for testing the valve, but you can also use it to bleed your brakes plus perform a lot of automotive maintenance.

In using the vacuum tester, all you need to do is see if the needle holds as you apply vacuum to your EGR valve. If it holds, it is a very good sign that your valve is working perfectly, but if the needle does not hold, it means that the diaphragm inside the valve is bad and needs to be replaced. If the needle holds, allow it to stay for some time to check if there is any pressure loss.

If you decide you don’t want to spend money purchasing a vacuum tester, there’s another way to do this. The first thing you do is to locate your EGR valve. You can take a look at the manufacturer’s guide of your vehicle to help you with this. Then put on your vehicle’s engine and rev your engine to about 2000 rpm. Gently create access to your valve and place your hand on it.

If your valve is working properly, you will observe a component inside the valve moving up and down. You can rev your engine a couple of times to be sure you are getting the movement. If you do not observe this movement, then it is a sign that your EGR valve is faulty. Now that’s all it takes to test a vacuum type EGR valve.

For an electric EGR valve, you need to have a multimeter; this device will be used to do a resistance reading, referred to as an ‘ohms test.’ Once connected, you should see a reading of about 20 to 24 ohms. You can check the repair manual of your vehicle for this.

You can now carefully push back the harness connector. You will see about six terminals on the valve. Use the negative and positive probe of the multimeter to test the different terminals of the valve. As you test these terminals, observe if the reading is within the expected reading of your valve. If yes, then your valve is functioning properly. You can click on this YouTube Video – to get a visual presentation of this whole process. So that’s it! Simple and easy, right?

How to fix a bad EGR valve?

When a large number of carbon deposits on the internal surface of your EGR valve, it can cause the valve to clog, making it unable to efficiently carry out its function. This can lead to a lot of problems. When you have a bad EGR valve, there are two main solutions: cleaning the valve or replacing it.

But first, you will need a mechanic toolset to aid you in easily carry-out this process. Then make sure you put on your safety wear. Especially your goggles and hand gloves. Please do not trivialize the relevance of protective wear when planning to carry out any mechanical procedure. Make sure you wear them before performing any repair on your vehicle.

Below is an easy step process that will help you fix a bad EGR valve.

Step 1: Remove all electrical connections

First, remove any electrical connections or hoses attached to the EGR valve. Also, carefully remove the mounting bolts holding the valve.

Step 2: Check the valve openings for clogging and buildup

Also, cross-check the close connections on the engine itself. They’re often clogged with carbon, almost as bad as the valve itself. So, brush-off large carbon deposits with a plier. You can use the EGR system cleaner and a small brush to remove any extra residue.

Step 3: Check the EGR valve for debris

If the valve is clogged, use a good quality EGR System cleaner and a small brush to properly clean your EGR valve. Please ensure that no drop of this solution touches any electrical component in your vehicle’s engine system. You can read our previous article to know how to clean an EGR valve.

Step 4: check for heat damage.

Examine the EGR valve for damages caused by heat, aging, and carbon buildup. If it is damaged, purchase a new one but check for your vehicle’s recommended valve type as not all vehicles have the same type of EGR valve. Some valves are vacuum-controlled, while others are electronically controlled.

Step 5: clean the gasket

Also, inspect the gasket for any carbon deposits. If any, clean it with the system cleaner. If you notice your gasket is faulty, you can change it now before proceeding.

Step 6: Reinstall the EGR valve.

After the components have been cleaned and inspected, reinstall the EGR valve, the EGR gasket, and other loosed components. Make sure they are secured to the engine according to factory specifications. Please do not overly tightened the screws.

Step 7: Check for leaks.

Test the functions of the components by using the guides from the factory service and confirm there are no vacuum or exhaust leaks. You should take your vehicle for a drive and observe for any negative symptoms.

How to change the EGR valve?

Changing the EGR valve of your vehicle is also a very simple and easy process; in fact, it is similar to the steps outlined above. EGR valves can also develop faults due to aging, so knowing your EGR valve replacement time is very important; this would help avoid any further damages that could have occurred due to an aged valve. It will also help to continuously allow the smooth operation of your engine. This will show you how to change your EGR valve:

Remove any electrical connections or hoses: Reaching your EGR valve might prove difficult, so you have to remove any electrical connections or hoses attached to the EGR valve. This will create easy access to the valve. Take-off the screws holding the EGR valve to the engine. Usually, there are about two to four, depending on the vehicle. Scrape off the sealing material from the surface.

Put away your old EGR valve and Install the new EGR valve and gasket (if needed): This must be done according to factory specifications.

Finally, reattach hoses or electrical connections. Check the system. Test the function using the instructions from factory service and confirm that there are no vacuum or exhaust leaks.

It’s that easy! You can use any of the diagnostic scan tools to check for any errors, or you can just drive your car to see if you did a good job. You should not experience any of the symptoms listed above that indicates a bad EGR valve. If you still do, you can alert us to properly help you out with this process.

Frequently Asked Questions (FAQs)

Can a bad EGR valve cause a misfire?

Of course, a bad EGR valve can cause a misfire. It is mostly caused by clogged passages in your vehicle’s intake manifold. Your vehicle will also suffer from the defect, e.g., with a severe loss of power. Oil vapors increase the accumulation of carbon in the exhaust gas recirculation valve, which often leads to a stuck valve.

Suppose the EGR valve is always open, the quantity of air drawn decreases as a result of a high proportion of exhaust gas. The control unit reduces the injection quantity and also the engine output. This can also cause a misfire in your vehicle while driving.

If your vehicle’s EGR valve is damaged, the problem can spread to other components. You might also observe black smoke coming out of the exhaust. With time, it can lead to contamination in your vehicle’s intake manifold and also on the valves.

What happens when EGR solenoid goes bad?

Your vehicle’s EGR solenoid is another important engine component in your EGR system. A faulty EGR solenoid can cause engine performance issues, illuminating the engine check, engine knocks, or pings.

Exhaust gas recirculation (EGR) has the task of lowering the combustion temperature in the combustion chamber and reducing the emission of nitrogen oxides into the environment. As a rather inconspicuous but important component of the car’s exhaust system, the exhaust gas recirculation solenoid (EGR solenoid) opens and closes the connection between the exhaust manifold and the intake manifold. If your EGR solenoid is faulty, your engine can stop, and this problem can affect other parts as well.

What code will an EGR valve throw have?

The P0401 trouble code is related to your car’s exhaust gas recirculation (EGR) system, which controls an engine and reduces emissions. Suppose a computer-controlled valve gives a certain amount of gases back into your engine to be burnt with the air-fuel mixture. In a case like this, your EGR system is triggered under certain conditions.

P0407 is taken to be an OBD-II generic code for signifying problems with your vehicle’s EGR system if the signal sent by the circuit to the engine computer is abnormally low and not within your vehicle’s manufacturer’s accepted parameters.

While a P0407 reading can be due to grounding issues or a bad engine computer, and P0406 code is faulty Sensors, especially if your EGR valve is having issues.

Should the EGR valve be open or closed?

The EGR valve can either open or close, depending on its operation. The EGR valve has about two main settings: open and closed. This position may vary at any point of operation. Your vehicle’s EGR valve closes when the engine kicks-off. When idling at a low speed, a small amount of power is needed, and therefore a small amount of oxygen is released.

But if the engine is idled at high speed, it will require a large amount of power, causing the EGR valve to open to about 90%. The EGR valve should be able to close and open as when needed to allow the smooth running of your vehicle’s engine. If the EGR fails to do this, it means that your EGR valve is clogged, and it is due for a cleaning. It can also mean that your valve is damaged.

What causes EGR valve failure?

If there is a fault in the EGR system, it can cause the EGR not to function properly. Your vehicle’s EGR valve can be faulty due to the accumulation of carbon deposits in its internal surface, pitting, burnt valve, a damaged diaphragm for a vacuum-type EGR valve, or distortion of the valve seat. This problem can also have the following causes:
Poor engine management

Constant short distance drive and from the emulsion of oil-water formation (especially in the winter months).
Intake of oily air due to worn valve stem seals, malfunction in your vehicle’s engine ventilation, excessive engine wear, or oil overfill.

Another possible source of errors that can lead to the failure of your EGR valve is a damaged engine cooling system.

How much does it cost to replace the EGR valve?

The new EGR valve can costs an average of $67, depending on the vehicle’s model and manufacturer. The prices for brand new EGR valves are usually kept within a range. It might even cost up to $167. The repair costs can increase if your vehicle’s connections, lines, or seals also have to be replaced.

The price for fixing the EGR valves are most times limited. The new EGR valve can cost from $269 depending on the vehicle type. The total cost is between $255 and $321. These include a diagnosis.

Final Words

Symptoms of a bad EGR valve can sometimes be mistaken for other faults in the engine system due to the similarity in the symptoms as with other faulty engine components. Hopefully, you can now identify the various symptoms that reflect a bad EGR valve and also how to fix this issue easily. But make sure you are certain of the cause before changing or removing any component in your engine system to avoid further unnecessary issues.

In case you’re experiencing any difficulty in some areas, you can reach out to us or your local mechanic to help you out with any issue you might be struggling with.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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