EXHAUST GAS RECIRCULATION VALVES (EGR) Usually found between the exhaust manifold and the intake manifold, the EGR valve helps to reduce the amount of harmful emissions by allowing some of the exhaust gases to venture back into the engineÂs combustion chamber where they are mixed with fresh intake air. This results in a lower peak combustion temperature and in-turn, reduces the amount of NOx produced by the engine. EGR Valves are prone to becoming clogged up with carbon deposits which can cause the valve itself to stick open or closed. A failed EGR valve usually results in increased fuel consumption, rough idle and will often put the vehicle into limp mode. Due to the increased level of emissions, it will also cause the vehicle to fail its MOT.
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