Dual EGR Control Solenoids

The control of EGR operating air pressure requires 2 types of solenoids: a vent type which is normally open to the atmosphere, unless the solenoid is energized, and a pressure type solenoid which is normally closed, blocking air pressure flow to the EGR system, unless the solenoid is energized. When the ECA senses a need for increased EGR flow, it energizes the solenoids and allows air pressure to the system and stops the venting process.