1. The EGR valve is located on the intake manifold, near the carburetor. Most problems with this emission system are caused by the EGR valve being stuck or corroded.
2. Manually press down on the diaphragm located under the EGR valve (the engine must be cold to prevent burns). With a little effort, the diaphragm should move up and down within the casing.
3. If the diaphragm does not move or only moves with a lot of force, replace the EGR valve with a new one. If the condition of a valve is in any doubt, compare its diaphragm displacement with that of the new valve.
4. For further information on the exhaust gas reburning system, see Section 6.