EGR Control Solenoid: Description and Operation

EGR Valve Location/Installation:

EGR System Vacuum Control Components And Hoses:

Exhaust Gas Recirculation (EGR) Valve Vacuum Solenoid Circuit Diagram:

Purpose:
The Exhaust Gas Recirculation (EGR) vacuum control has a computer controlled solenoid that uses "Pulse Width Modulation" (PWM) to regulate the amount of vacuum applied to the EGR valve. This means that the PCM turns the solenoid "OFF" and "ON" many times a second and varies the amount of "ON" time (pulse width) to vary the amount of vacuum to the EGR valve.

Operation:
The duty cycle (amount of "ON" time Vs. "OFF" time for each cycle) is given in percent "ON" time and calculated by the PCM based on information from the coolant temperature, intake air temperature, manifold absolute pressure (MAP), throttle position, vehicle speed, engine rpm, and PNP switch. There should be no EGR function when in park or neutral, TPS input below a specified value, or TPS indicating Wide Open Throttle (WOT).