Exhaust Gas Recirculation (EGR) Cooler System Monitor - Transit

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2018 Ford Transit-350 HD, 2018 Ford Transit-350, 2018 Ford Transit-250, 2018 Ford Transit-150, and 2018 Ford F-550 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

The functionality of the EGR cooler system, including the EGR cooler bypass valve and the exhaust gas temperature bank 1 sensor 2 (EGRT12), is monitored by comparing the measured EGR gas temperature downstream of the EGR cooler assembly, with the measured engine coolant temperature when certain engine operating conditions exist. The operating conditions in which this detection can occur are the monitor entry conditions. Changes in engine operating conditions cause a delay before the changes are reflected in the EGR cooling system temperatures. The entry conditions timers must complete before the monitor is complete. When a condition feeding a timer is no longer met, the timer resets. Excessive EGR cooling and insufficient EGR cooling can be detected using the EGR cooler bypass monitor.

The insufficient EGR cooling monitor detects when the EGR is being cooled less than desired, such as when the EGR cooler bypass is stuck in the bypass position. The entry conditions for the insufficient EGR cooling monitor must be met for the monitor to be enabled. Once the entry conditions are met and while they continue to be met, the measured exhaust gas temperature downstream of the EGR cooler assembly is compared to a threshold based on measured engine coolant temperature. A typical value for this threshold is 150° C (270° F) above engine coolant temperature. If the measured exhaust gas temperature downstream of the EGR cooler assembly is greater than the threshold, for a predetermined amount of time, a DTC is set.

The excessive EGR cooling monitor can detect when EGR is being cooled greater than desired, such as when the EGR cooler bypass is stuck in the cooling position. The entry conditions for the excessive EGR cooling monitor must be met for the monitor to be enabled. Once the entry conditions are met and while they continue to be met, the measured exhaust gas temperature downstream of the EGR cooler assembly is compared to a threshold based on measured engine coolant temperature. A typical value for this threshold is 30° C (54° F) above engine coolant temperature. If the measured exhaust gas temperature downstream of the EGR cooler assembly is less than the threshold, for a predetermined amount of time, a DTC is set.