OBD Operation Summary for 6.7L Diesel - MotorCraftService.com

DEF Pressure SensorThe DEF pressure control system uses the measured DEF pressure in a feedback control loop to achieve thedesired DEF pressure. The DEF injection algorithm uses actual DEF pressure in its computation of DEF injectorpulse width.The DEF sensor is a gauge sensor. Its atmospheric reference hole is near the electrical connector. The DEFpressure sensor has a nominal range of 0 to 0.8 MPa (0 to 8 bar, 0 to 116 psi). This pressure range is above themaximum intended operating pressure of 0.5 MPa. The sensor voltage saturates at slightly above 0.5 and slightlybelow 4.5 volts.DEF Pressure SensorDEF pressure is often a vacuum when the system purges after running. Vacuums cannot be measured by theDEF pressure gauge sensor as voltages will not be lower than 0.5 Volts.DEF Pressure Sensor Transfer FunctionDEF Pump Pressure (PSI) = 29 * Voltage - 14.5Volts Pressure, MPa (gauge) Pressure, psi (gauge)5.00 0.8 1164.50 0.8 1163.50 0.6 872.50 0.4 581.00 0.1 140.500 0.0 00.250 0.0 0FORD MOTOR COMPANY REVISION DATE: FEBRUARY 9, 2012 09.01.00.02-PAGE 99 OF 157