EGR Control Solenoid: Description and Operation

EGR Solenoid Valves:

PURPOSE
Control EGR valve operation in accordance with Powertrain Control Module (PCM) output signals.



OPERATION
The system consists of two solenoids, EGR Control (EGRC) and EGR Vent (EGRV). These two solenoids operate with the EGR Valve Position (EVP) Sensor to form a feedback loop. The EGRC and EGRV solenoids regulate vacuum to the EGR valve to maintain the EVP sensor output at a value set by the PCM according to various engine parameters.

The PCM controls the EGR valve by alternately energizing the EGRC and EGRV solenoids. When energized the EGRC solenoid applies vacuum to the EGR valve and alternately when energized the EGRV solenoid vents vacuum from the EGR valve. The two solenoids operate back and forth to achieve the correct EGR valve position.