What is a erg valve

An egr valve is an emmsion component to help lower exhaust emmisions.it also helps with pinging, this is a valve that takes exhuast and recirculates it back into engine to be reburned and is controlled by the computer, the computer with vacuum. the computer sends a signal to the vacuum solenoid to open that allows vacuum to flow through to the egr valve so it can open to allow exhaust back into engine, the computer uses a signal form the egr feedback sensor, this sensor is used so that the computer knows the egr is working correctly by monitoring the exhaust preasure, there are two hoses connected to this sensor and when the egr valve opens the preasure drops a little going to the feedback sensor which changes the signal to computer so that computer knows valve is working. the most common reasons for the system not to work is the vacuum solenoid goes bad and doesnt allow vac to flow to the valve, the next thing that could go is a hose to feedback sensor falls off or breaks causing a leak and then the preasures dont change, the last thing is the egr valve itself. a could way to test the valve is to remove vac hose and connect a vac pump to it and apply vacuum with engine running and you should see idle drop and engine speed lower, this means valve is good, the feedback sensor you would need a scan tool to watch readings or a meter to watch readings and see if they change as you open valve, the last test is the egr vac solenoid, you will need to unplug connector and turn engine on, then test connector you will have power to one wire or ground, lets say you have power to connector but no ground you will mark the power wire so not to mix up wires. next connect connector and apply a ground jumper wire to terminal that has no ground, dont connect to power connector, now see if the egr valve opens, some of these are set up with power and ground already and the computer removes one to open the valve, so first try to test both connectors at the solenoid and if theres power and ground with engine running then all you need to do is check the hose to egr valve for vacuum when you remove the connector from the solenoid. by removing the connector from the solenoid you will be opening it and vac should flow to egr valve, note this is only if when you test the connector theres power on one wire and ground on the other. hope this helps.heres pictures of each component. good day.

Eric, an EGR valve is an Exhaust Gas Re circulation valve that meters a small amount of exhaust gas into the intake. The effect is to lower oxides of nitrogen (an emission). Exhaust gases are normally not combustible, so if this valve fails your engine runs really poorly, especially at lower speeds. EGR valves are a high maintenance/ replace often part....But, do replace yours, the valve is essential.