Intrusive EEGR System Monitor

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2010 Mercury Milan, 2010 Mercury Mariner, 2010 Mercury Grand Marquis, 2010 Lincoln Town Car, and 2010 Lincoln Navigator L. However, it is still accessible from the selected car via links, so may be relevant.

When EGR is delivered into the intake manifold, intake manifold vacuum is reduced and thus manifold absolute pressure (MAP) is increased. A MAP sensor and inferred MAP are used by this monitor to determine how much EGR is flowing. A MAP sensor located in the intake manifold measures the pressure when EGR is being delivered and when EGR is not being delivered. The pressure difference between EGR on and EGR off is calculated and averaged. If the vehicle is equipped with a MAF sensor, the monitor also calculates and averages an inferred MAP value in the above calculation and resulting average. After a calibrated number of EGR on and EGR off cycles are taken, the measured and inferred MAP values are added together and compared to a minimum threshold to determine if a flow concern (P0400) in the EGR system has occurred.