EGR Control Solenoid: Description and Operation

EGR VSV:

The EGR valve is controlled by the ECM. The ECM uses a Solenoid Valve (VSV) to control vacuum to the EGR modulator, then to the EGR itself. The EGR valve is turned "ON" when the ECM senses various inputs from sensors.

Under any one of the following conditions, the ECM closes the vacuum passage of the VSV. In this state, as the vacuum is not transmitted to the EGR valve, it remains closed.

^ When engine coolant temperature is low
^ When engine is running at high speed (higher than 6000 rpm)
^ When barometric pressure is low (at high altitude)
^ When engine is running at high load
^ When transmission is in lock-up condition (for A/T Federal emission vehicle)
Other than the above, the EGR valve opens and closes in accordance with the EGR modulator operation.