Exhaust Gas RECIRCULATION: Operation: Notes

When engine coolant is below 63° F (17° C), no EGR takes place. When engine coolant is above this temperature, EGR is permitted except when the engine is at idle or full throttle. The vacuum control valve and an orifice regulate vacuum flow to the EGR valve at different engine speeds, ensuring that the EGR flow is correct. Individual system components function as follows: