Exhaust Gas Recirculation (EGR) System

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Overview

The EGR system controls the NOX emissions. Small amounts of exhaust gases are recirculated back into the combustion chamber to mix with the air to fuel charge. The combustion chamber temperature is reduced, lowering NOX emissions.

The EGR system consists of an electric motor EGR valve integrated assembly, a MAP sensor, differential pressure feedback EGR sensor, PCM. Operation of the system is as follows:

The EGR system receives signals from the CHT sensor, TP sensor, CKP sensor, and the MAP sensor to provide information on engine operating conditions to the PCM. The engine must be warm, stable, and running at a moderate load and RPM before the EGR system is activated. The PCM deactivates the EGR during idle, extended wide open throttle (WOT), or whenever a concern is detected in an EGR component or EGR required input. The PCM calculates the desired amount of EGR for a given set of engine operating conditions.

The monitor checks the electric EGR valve circuits for opens and shorts. The monitor compares the differential pressure feedback EGR sensor to a calibrated value and the electric EGR valve commanded position to determine if EGR flow is present.

The monitor checks for the differential pressure feedback EGR sensor for opens and shorts. The differential pressure feedback EGR sensor hoses are tested for connection and restriction at idle. The PCM commands the EGR valve closed and the monitor tests for the differential pressure feedback EGR sensor to indicate no flow is present. The PCM commands the EGR valve open and the monitor tests the differential pressure feedback EGR sensor voltage to indicate flow is present. The auto stop start feature requires the hose tests to run during off idle conditions.

The intake manifold pressure is higher when the EGR is flowing than when it is not flowing. When the exhaust gas is delivered into the intake manifold, the MAP sensor reading increases.

The exhaust manifold provides a source of exhaust gas to the EGR orifice tube and EGR valve.