EGR Backpressure Transducer: Description and Operation

Back Pressure Transducer:

LOCATION
Near the throttle body.

PURPOSE AND OPERATION
Exhaust gas back pressure operates a diaphragm in the EGR modulator to open and close the valve. The opening and closing of this valve controls the vacuum transmitted to the EGR valve.
Under low load conditions exhaust pressure is low, allowing the modulator spring to open the vacuum passage to outside air. Less vacuum is transmitted to the EGR valve and only a small amount of exhaust gas enters the intake manifold.

Under high load conditions exhaust pressure is high, pushing the modulator diaphragm up to close its valve. More vacuum is transmitted to the EGR valve and a larger amount of exhaust gas enters the intake manifold.