Circuit Description

Vacuum to EGR is controlled by EGR vacuum control signal solenoid, which regulates vacuum by varying the duty cycle (on-time). The duty cycle is calculated by the PCM based on data from the ECT sensor, MAF sensor and RPM. PCM uses MAF and IAT sensor data to determine when to enable the EGR system. EGR operation is prevented when transmission is in Park or Neutral, throttle angle is less than the predetermined value or at wide open throttle.