Emission Control Components Description

EGR Control System:

CIRCUIT OPERATION
The EGR control system is used to allow precise control of the EGR valve. The ECU receives signals from the crank angle sensor, idle switch, engine temperature sensor and the ignition switch to determine if EGR operation is warranted. The ECU supplies the ground circuit for the solenoid.

Vacuum Solenoid:

EGR CONTROL SOLENOID
Only when the following conditions are met does the ECU energize the solenoid which redirects vacuum from the source port and valve port to the source port and vent port PREVENTING the EGR valve from operating:
1. Engine starting.
2. High engine rpm.
3. Low coolant temperature.
4. High coolant temperature.
5. Engine idling.
6. Crank angle sensor fail safe operation.
Refer to EMISSION CONTROLS for further description of the EGR valve.