EGR Solenoid

The EGR solenoid assembly is mounted at the top, left rear of the engine. The PCM controls the time the EGR solenoid to regulate the vacuum to the EGR valve. This regulates the amount of EGR. The PCM calculates the amount of EGR based on engine speed and accelerator pedal position. The PCM is programmed to vary the ON and OFF time of the EGR solenoid, based on these two inputs. To monitor the PCM control of EGR, an EGR control pressure/BARO sensor is used to measure the amount of absolute pressure in the EGR vacuum line. If a minor variation in calculated EGR and actual EGR as monitored by the EGR control pressure/BARO sensor, the PCM makes a correction. If the variation exceeds an amount in excess of what the PCM can correct for, an error is detected by the PCM and the system will go into default.

When the PCM recognizes the operating range for no EGR, the EGR vent solenoid operates to allow rapid venting of vacuum to the EGR valve.