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Exhaust Gas Recirculation (EGR)

What is it and what does it do?


An EGR valve is a valve in your vehicles intake system that under certain operating conditions recirculates exhaust gas back into your engine to be re-burnt. Why would you want dirty exhaust gas back in your clean intake you ask? It’s all about reducing harmful emissions your vehicle produces. One of these harmful greenhouse gases is nitrogen oxide (NOx). Nitrogen oxide is a by-product of high combustion temperature and excess oxygen (O2). By recirculating exhaust gas back into the combustion chamber and diluting the oxygen this in turn reduces this combustion temperature which then reduces harmful nitrogen oxide gases.

How can we help?

EGR valves are probably the most common emission control system to fail particularly on diesel vehicles. The most common cause of failure is carbon build-up stopping the valve opening and closing fully or completely stopping the valve from moving. EGR valve faults can cause various running issues and warning lights on your dash. With our specialised computers and diagnostic equipment, we can quickly determine what’s going on and how to rectify it.

EGR system diagram

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