EGR (Exhaust Gas Recirculation) valves are designed to open and close at specific points during the engine cycle to allow carbon dioxide into the combustion chamber, thereby cooling the chamber and its contents to reduce the amount of gaseous NOx (nitrogen oxide) emissions. There are a few symptoms that indicate EGR valve stickiness, and they should be resolved as soon as possible to avoid engine damage.
EGR Valve Stuck in the Closed Position
An EGR valve that is stuck in the closed position will raise the temperatures in the combustion chamber, creating a knocking or pinging. This is especially noticeable in situations where the vehicle is accelerating or cruising. EGR valves stuck in the closed position are especially dangerous for vehicles equipped with turbos since the high temperature and constant exposure will eventually cause the turbo to seize.