Negative Backpressure EGR Control Solenoid

EGR System:

OPERATION:
To regulate EGR flow an ECM controlled solenoid is used in the vacuum line. This is a normally closed solenoid vacuum valve which is opened when the ECM completes the ground. The ECM will energize the EGR solenoid (EGR ON) when the engine is warm and above idle. There is little EGR flow at wide open throttle due to lack of engine vacuum.