EGR Solenoid: Function, Symptoms, and FAQs

If you smell a foul or unburnt fuel smell coming from your vehicle’s exhaust, don’t ignore it. It might be due to a fault in the exhaust gas recirculation (EGR) system, specifically the EGR solenoid.

As if the odor isn’t unpleasant enough, the effects of a damaged EGR solenoid could affect your vehicle’s overall operation. The best way to prevent problems that require costly repairs is to get to know the part, from its functions and symptoms when it’s failing to whether you can drive while it’s faulty.

What Is the EGR Solenoid?

The EGR solenoid is an electronic vacuum valve that distributes engine vacuum to the EGR valve. It lets exhaust gases enter the intake manifold by opening a passage when the car computer prompts it.

This solenoid lowers the combustion temperature, preventing heat damage to the engine block, head gasket, cylinder, and pistons. It also reduces the vehicle’s nitrogen oxide emissions. It essentially helps achieve the engine’s best performance, efficiency, and emissions.

It does so by allowing already burnt combustion gases to enter the combustion chamber to take up space so less fuel is needed.

What Are the Symptoms of a Bad EGR Solenoid Valve?

Common symptoms of a bad EGR solenoid and valve include unpleasant smells, an illuminated check engine light, engine spark knocks, and engine performance issues.

Unburnt Fuel Smell

A damaged EGR valve results in an increased temperature in the combustion chamber, which releases hydrocarbons mixed with nitrogen oxide emissions. These gases are hazardous and have a strong odor.

Illuminated Check Engine Light

If the computer detects any issues with the EGR solenoid, circuit, or system, it might illuminate the check engine light.

However, keep in mind that an illuminated check engine light could indicate different issues. To determine whether it lit up due to an EGR solenoid valve issue, retrieve the trouble code the car’s computer logged using a scan tool. You can also look out for other bad solenoid symptoms.

Engine Pinging or Knocking Sounds

When the EGR solenoid fails, it disables the EGR system from recirculating exhaust gases. This could cause excessively lean conditions, resulting in engine pinging or knocking.

The high-frequency pressure waves produced by the increased temperature forces parts of the engine to vibrate, causing the pinging noise.

Don’t disregard the pinging noise, as it could lead to serious engine damage, such as overheating spark plug points and combustion chamber surface erosion.

Engine Performance Issues

The EGR solenoid helps achieve optimal engine performance. Any damage to it could lead to issues, such as decreased power, acceleration, and poor fuel economy, mainly because the solenoid is also responsible for the proper air and fuel ratio.

The EGR system as a whole affects the engine, mainly because proper air-to-fuel mix is a crucial part of engine performance control.

Failed Emission Test

Emission tests check the engine exhaust gas emission rate. If you have a faulty EGR solenoid that’s causing increased nitrogen oxide emissions, you likely fail the test.

Do note that this test cannot precisely check the condition of the EGR. Try to have it examined by a professional if you fail the emission test.

What Happens When the EGR Solenoid Goes Bad?

Engine performance issues are the most prominent effects of a bad EGR solenoid. They include lowered capability, acceleration, and increased emissions.

Additionally, you may also notice poor fuel efficiency. This is because the EGR system is responsible for mixing the proper air and fuel ratio. A faulty one results in the engine burning off, eating up a full tank of gas in no time.

What Causes the EGR Solenoid to Go Bad?

Some of the common reasons why an EGR solenoid develops issues include a faulty temperature sensor, a clogged EGR pipe, and a sticky EGR valve.

Faulty Temperature Sensor

Whenever your car burns fuel, it produces nitrogen oxide, a harmful gas. As such, the EGR valve helps regulate it by ensuring the ideal fuel efficiency is met by opening up the valve only at certain times.

To time it properly, the EGR valve relies on the information from the EGR temperature sensor, which monitors the exhaust temperature. When the temperature rises, the valve opens wider to compensate. And when the temperature cools down, the valve closes.

A faulty temperature sensor could send incorrect information to the computer, causing it to mistime its operation. Not only is it harmful to your vehicle, but it could also harm you and the environment due to the increased nitrogen oxide emissions.

Replace your temperature sensor once you pinpoint that it’s the culprit behind your EGR solenoid problems. Replacing it typically costs somewhere between $400 and $440, depending on the replacement piece and the labor fee.

Clogged EGR Pipe

The EGR system directs exhaust back to the engine through a section of tubing called the EGR pipe. The exhaust has contaminants, such as soot, that can build up on the pipe walls.

The soot could become thick enough to block the passageway over time. This leads to an increase in engine temperature as the EGR system becomes inefficient.

Sticky EGR Valve

The contaminants that clog the EGR pipe could also affect the EGR valve, building up into a sticky mess that would make it difficult for the valve to open and close. This results in an increase in engine temperature, as the exhaust won’t properly flow.

Can I Drive With a Bad EGR Solenoid?

Your vehicle will still move even with a bad EGR solenoid. However, driving with one is inadvisable due to the engine issues it can cause. This is because the solenoid is responsible for proper air and fuel mixture, among other things.

When faced with any of the symptoms above, it’s best to contact a mechanic for an accurate diagnosis.

Get a Replacement EGR Solenoid You Can Rely On

You should resolve exhaust system issues before your vehicle is due for its next emissions test. Ignoring a damaged or faulty EGR solenoid can result in additional problems that cost more to fix. Restore your vehicle’s exhaust system to peak condition with a replacement EGR solenoid from CarParts.com.

At CarParts.com, you can get auto parts and accessories you can rely on. We exclusively source our EGR solenoids from trusted manufacturers to ensure quality parts that work like clockwork. Finding the product that fits your car or truck is easy with our website’s integrated vehicle selector. Once you find what you need, you can order it in specific quantities or in a bundle with other parts. If you’re in the continental US and place your order by 12 p.m ET, your new EGR solenoid can reach your doorstep in as fast as two business days.

There’s no time like the present to get a replacement EGR solenoid for your car. Look at our extensive selection of EGR solenoids and find one that fits your requirements today!