EGR Valve: Description and Operation

Fig. 50 EGR Component Locations:

The EGR system consists of the EGR valve, exhaust recirculation lines, 50°C thermovalve, vacuum ports on the throttle valve, and vacuum lines.
A vacuum signal from the throttle valve controls a proportional introduction of exhaust gases into the intake system. This action lowers the temperature in the combustion chambers therefore reducing oxides of nitrogen in the exhaust gases. The EGR system is operational when the engine temperature is above 50°C (122°F). Below 50°C (122°F) the thermovalve prevents application of vacuum to the EGR valve. The EGR valve is operational under all load conditions except idle (closed throttle) and full load.