EGR Electronic Vacuum Regulator Solenoid: Description and Operation

EGR Control Solenoid:

To regulate EGR flow, an ECM controlled Electronic Vacuum Regulator Valve (EVRV) solenoid is used in the vacuum line. The ECM uses information from the following sensors to enable the EVRV solenoid:

^ Throttle Position Sensor.
^ P/N Switch
^ Manifold Absolute Temperature (MAT) Sensor

The ECM uses the information from the following information sensors to regulate the EVRV solenoid:

^ Engine Load
^ Coolant Temperature
^ Distributor (rpm signal)
^ Torque Converter Clutch (TCC)

A diagnostic switch is also part of the EGR control and monitors vacuum to the EGR valve. This switch will trigger a "SERVICE ENGINE SOON" LIGHT, and set a Code 32 in the event of vacuum circuit failure.


The EGR vacuum control, (EVRV solenoid) uses pulse width modulation. This means the ECM turns the solenoid "ON" and "OFF" many times a second and varies the amount of "ON" time (pulse width) to vary the amount of EGR.