My Vauxhall Zafira 1.7 cdti ecoflex engine, cleaning the Exhaust Gas Recirculation valve.
Over time this gets clogged up with carbon/exhaust deposits and becomes sticky. If left too long it will jam either open or closed and reduce engine performance.
The EGR is there to reburn exhaust gases to reduce noxious gasses being emitted from the exhaust.
This video I show how to remove and clean it on the 1.7 diesel A17DTJ engine.