EGR Control Solenoid: Description and Operation

Exhaust Gas Recirculation (EGR) Circuit:

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

Operation:
The PWM is calculated by the ECM based on information from the coolant temperature, air flow and engine rpm. There should be no EGR function when in park or neutral, TPS input below a specified value, or TPS indicating Wide Open Throttle (WOT).

Location:
The EGR solenoid is mounted to the left side of the intake manifold.