EGR System: Operation

When engine is below operating temperature, no exhaust gas recirculation is obtained. Increase in engine temperature allows control valves to regulate vacuum to EGR valve for gas recirculation.

Vacuum modulator is used to relieve exhaust backpressure, balance atmospheric pressure and vacuum allowing EGR operation. The EGR cooler, used on the Cressida, Land Cruiser and Supra assists in reducing exhaust gas temperature before entering combustion chamber.