2005 MY OBD System Operation Summary for Gasoline Engines
2005 MY OBD System Operation Summary for Gasoline Engines
2005 MY OBD System Operation Summary for Gasoline Engines
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The Delta Pressure Feedback EGR Monitor is a series of electrical tests and functional tests that monitor variousaspects of EGR system operation.First, the Delta Pressure Feedback EGR (DPFE) sensor input circuit is checked <strong>for</strong> out of range values (P1400 orP0405, P1401 or P0406). The Electronic Vacuum Regulator (EVR) output circuit is checked <strong>for</strong> opens and shorts(P1409 or P0403).DPFE EGR Electrical Check <strong>Operation</strong>:DTCsMonitor executionMonitor SequenceSensors OKMonitoring DurationP1400 or P0405 - DPFE Circuit LowP1401 or P0406 - DPFE Circuit HighP1409 or P0403 - EVR circuit open or shortedContinuous, during EGR monitorNone4 seconds to register a malfunctionTypical DPFE EGR electrical check entry conditions:EGR system enabledTypical DPFE EGR electrical check malfunction thresholds:DPFE sensor outside voltage: > 4.96 volts, < 0.0489 voltsEVR solenoid smart driver status indicates open/shortThe DPFE sensor is a ceramic, capacitive-type pressure transducer that monitors the differential pressure across ametering orifice located in the orifice tube assembly. The differential pressure feedback sensor receives this signalthrough two hoses referred to as the downstream pressure hose (REF SIGNAL) and upstream pressure hose (HISIGNAL). The HI and REF hose connections are marked on the aluminum DPFE sensor housing <strong>for</strong> identification(note that the HI signal uses a larger diameter hose). There are two styles of DPFE sensors. The newer, plastichousing utilizes a 1.0-volt offset (zero reading) whereas the older, aluminum housing utilizes either a 0.5-volt or1.0-volt offset. See the ESM EGR section <strong>for</strong> the 0.5-volt offset transfer function. The slopes <strong>for</strong> either offset areidentical.DPFE Sensor Transfer FunctionDPFE volts = Vref [( 0.683 * Delta Pressure) + 20 ] / 100Volts A/D Counts in PCM Delta Pressure, Inches H 2 O0.0489 10 -27.90.76 156 -7.01.0 204 01.24 254 7.02.02 415 303.05 624 604.07 834 904.96 1015 116Note: EGR normally has large amounts of water vapor that are the result of the engine combustion process. Duringcold ambient temperatures, under some circumstances, water vapor can freeze in the DPFE sensor, hoses, aswell as other components in the EGR system. In order to prevent MIL illumination <strong>for</strong> temporary freezing, thefollowing logic is used:FORD MOTOR COMPANY REVISION DATE: APRIL 28, 2004 PAGE 47 OF 131
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