OBD Operation Summary for 6.7L Diesel - MotorCraftService.com

Typical EGR Closed-loop Control – Threshold MapRPM/TRQ 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 375005010015020025030035040045050055060065070075050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 5050 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50Mass Airflow Closed-loop Control Limits MonitorDuring DPF regeneration the control system is closed-loop around air mass flow and the limits of the controlsystem are monitored by observing the control deviation calculated as the difference between the desired air massflow and the actual mass air flow determined from the MAF sensor. If no air system faults are present, the controllimit monitor function continuously during closed-loop operation. Separate threshold maps are used to indicate thecontrol system operation is at its limits for both the high flow and low flow extremes. Control limit threshold mapsare a function of engine torque and engine speed and are based upon the expected distribution of deviations froma statistical sampling. An up/down debounce counter is used that counts upward when the control deviationexceeds the calibrated threshold and counts downward when the control deviation falls below the threshold for thecase where the system operation is limited mass airflow higher than the controller set point. Similarly, the up/downcounter counts upward when the rate deviation falls below a calibrated threshold and counts downward when itrises above the threshold for the case where the system operation is limited to mass airflow lower than thecontroller set-point. Once the counter exceeds calibrated thresholds for either case a malfunction is detected.FORD MOTOR COMPANY REVISION DATE: FEBRUARY 9, 2012 09.01.00.02-PAGE 49 OF 157