1. The EGR valve is bolted to the rear cylinder head on the transmission side. The most common cause of malfunctions in the EGR system is a stuck or oxidized EGR valve.
2. Cold (not to get burned) reach the bottom of the EGR valve and press its diaphragm. The diaphragm should move already with a moderate pressure force.
3. If the diaphragm starts to move only with very strong pressure, or does not give in at all, replace the EGR valve. If you are unsure about the condition of a valve, compare it to a new one or a known good one.
4. Detailed information on the functioning of the EGR system is given in Chapter Engine management systems.