The EGR valve takes exhaust gas from the exhaust manifold, and passes it back into the engine for reburning...if that doesn't sound daft. This has the result of lowering the exhaust gas temperature, which is kind to the turbo, and also reduces the oxides of nitrogen pollution, which is kind to the environment. So, look at your exhaust manifold, and spot a round canister about 50mm diameter with a small rubber pipe going to it...thats the egr. It also has a larger metal pipe on the bottom of it which heads for the inlet manifold. Blocking off the small rubber pipe should disable the EGR if its working.
John
July 2009