Grand Caravan FWD V6-3.0L VIN 3 (1999)
When the PCM energizes the solenoid, vacuum does not reach the transducer. Vacuum flows to the transducer when the PCM de-energizes the
solenoid.
When exhaust system back-pressure becomes high enough, it fully closes a bleed valve in the transducer. When the PCM de-energizes the solenoid
and back-pressure closes the transducer bleed valve, vacuum flows through the transducer to operate the EGR valve.
De-energizing the solenoid, but not fully closing the transducer bleed hole (because of low back-pressure), varies the strength of vacuum applied
to the EGR valve. Varying the strength of the vacuum changes the amount of EGR supplied to the engine. This provides the correct amount of
exhaust gas recirculation for different operating conditions.
