Q: What is the function and location of the EGR valve in an engine?
A: The EGR system consists of exhaust gases that are metered into the intake manifold either through the manifold passages or through outside pipes, which connect the exhaust manifold to the EGR valve and the intake manifold. These exhaust gases combine with the air/fuel mixture inside the manifold. At high combustion temperatures, the dilution of the air/fuel mixture by exhaust gases lowers combustion chamber temperatures resulting in reduced levels of oxides of nitrogen (NOx) as a natural byproduct or high combustion temperatures. The PCM regulates how much exhaust gas is mixed with air/fuel mixture depending on engine operating conditions. It is also under direct control by PCM and is digitalized. This digital EGR valve meters exhaust gases into intake manifold independently from intake manifold vacuum and can better regulate it than any vacuum controlled EGR valve. A few common issues with such engines are rough idling or stalling at idle; rough engine performance during light throttle application, and stalling during deceleration. In order to check this valve, special electronic diagnostic equipment must be used; it should only be done at dealer service departments or other qualified repair facilities. This valve is located on the left end of the engine behind the throttle body. Disconnect electrical connector from EGR valve, remove two nuts for EGR valve mounting and pull out EGR valve itself to replace it . The removal process needs to be reversed during installation.