I had the EGR valve and solenoid replaced and I'm not sure they needed to be replaced.
The EGR valve diverts exhaust gas back into the intake manifold to take up space and prevent the formation of NOx, a polluting gas formed inside the cylinder at temperatures above 2500 degrees.
they are cheap replace it
EGR means exhaust gas recirculator. it extracts unburned gas from the exhaust and returns it to the intake to be burned
The Exhaust Gas Recirculation valve allows a metered amount of exhaust to be drawn into the intake to be re-burned with the fuel and air mixture. The purpose for that is to introduce an inert gas to the mixture which lowers combustion temperatures. The reason for lowering combustion temperatures is to reduce the emissions of NOX from the tailpipe. I'm not sure if it needed to be replaced either, but if your check engine lamp doesn't come on anymore, then it probably did need it.
