EGR Backpressure Transducer (G20 & Q45)

A backpressure transducer is installed in vacuum hose to EGR valve. During periods of low exhaust backpressure, EGR is not desirable and transducer allows EGR vacuum signal to bleed off to atmosphere. When backpressure increases, internal diaphragm of transducer lifts, blocking off vacuum bleed, allowing vacuum to pass through transducer and react upon EGR diaphragm.