EPR Solenoid

A vacuum operated EPR valve is used to increase exhaust backpressure under certain operating conditions in order to increase the amount of exhaust gasses available for recirculation. Operating vacuum for the EPR valve is controlled by a solenoid which receives battery voltage when the ignition switch is in the on position. The EPR solenoid ground path is completed through the ECM, and when the solenoid is ``on'' vacuum is applied to the valve.