California

EGR Duty Solenoid And Vacuum Switching Valve:

EGR system control and optimum EGR volume are determined by the ECM based on three main signals:

1. Engine RPM
2. Intake air volume
3. Coolant temperature

To operate the system, the ECM controls a duty solenoid which in turn regulates vacuum to the EGR valve. Also incorporated into the system is an ECM controlled vacuum switching valve for EGR cut under specified conditions.