A critical piece of your engine management system, the EGR valve recirculates exhaust gas to a specific part of your intake system for optimum fuel efficiency and reduced emissions. This helps reduce harmful nitrogen oxides or NOx, a dangerous gas that can harm your health and the environment when released into the atmosphere.
Its Job
The EPA recommends reducing NOx emissions to protect the atmosphere, which is why vehicles with an EGR valve have an emission control system to do just that. By allowing a certain percentage of your exhaust to re-enter the intake, your vehicle can change the way it burns fuel, lowering combustion temperatures by up to 150degC and reducing NOx production for cleaner, more efficient engines.
It’s a Vacuum-Controlled Unit
The evr valve on your car is a vacuum-controlled unit that can be accessed by sticking your fingers into the small opening of the metal disc and pushing the diaphragm to see if it moves. If it does not, it is likely clogged with carbon particles, which will require replacement.
It’s a Digital Valve
Most modern cars are equipped with digital EGR valves that work using a solenoid or stepper motor and a sensor to regulate the amount of exhaust gas that flows into your intake system. These valves are usually powered by a PWM (pulse width modulated) signal from your engine control unit to recirculate exhaust gas.
Your engine control unit has an indicator lamp that lights up when the EGR valve is open or closed to let you know about an issue. The light will stay on when the valve isn’t working correctly so you should always check for symptoms that indicate your faulty EGR valve.
You can also check the vacuum solenoid on your EGR valve if you have an electronically controlled one. Activate the solenoid with a scan tool and use the tool to measure vacuum at the end of the pipe – it should be greater than the maximum allowed by your manufacturer’s specification.
It Could Be Clogged
Your valve might be clogged with carbon deposits that are caused by normal wear and tear. If this is the case, a carburetor cleaner should dissolve the buildup of deposits, but you might need to replace your valve altogether if it is plugged with too much residue.
It Might be a Bad Idea
A clogged EGR valve can cause your car to run badly and pollute the air around you with exhaust gases that are not normally allowed to escape your vehicle. If you notice this happening, you should get it looked at as soon as possible.
It Might be a Safety Thing
A faulty EGR valve can allow carbon and other exhaust gases to enter the engine, potentially causing an explosion. This can be hazardous if your vehicle is in an accident and could lead to injury or even death.
A faulty EGR valve can also lead to knocking noises in the engine and loss of engine power. This can also make your car consume more fuel than it should and not give you the best gas mileage.