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HOMESERVICE MANUALSLINCOLN2009NAVIGATOR L RWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - POWERTRAIN DTC CHARTS & DESCRIPTIONS (EXCEPT DIESEL & HYBRID)DTC DIAGNOSISDTC P0401: - EXHAUST GAS RECIRCULATION (EGR) FLOW INSUFFICIENT DETECTED
2009 Lincoln Navigator L RWD

DTC P0401: - Exhaust Gas RECIRCULATION (EGR) Flow Insufficient Detected

2009 Lincoln Navigator L RWDSECTION DTC P0401: - Exhaust Gas RECIRCULATION (EGR) Flow Insufficient Detected
DTC P0401: - EXHAUST GAS RECIRCULATION (EGR) FLOW INSUFFICIENT DETECTED

Description:  The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the differential pressure feedback EGR sensor indicates that EGR flow is less than the desired minimum.
Possible Causes: 
  • Vacuum supply
  • EGR valve stuck closed
  • EGR valve leaks vacuum
  • EGR flow path restricted
  • EVR circuit short to voltage
  • VREF open to differential pressure feedback EGR sensor
  • Differential pressure feedback EGR sensor downstream hose is off or plugged
  • EVR circuit open
  • VPWR open to EGR vacuum regulator solenoid
  • Differential pressure feedback EGR sensor hoses are both off
  • Differential pressure feedback EGR sensor hoses are reversed
  • Damaged EGR orifice tube
  • Damaged EGR vacuum regulator solenoid
Diagnostic Aids:  Carry out the key on engine running (KOER) self-test and look for DTC P1408 as an indication of a hard fault. If DTC P1408 is not present, look for contamination, restrictions, leaks, and intermittent concerns.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
Crown Victoria,
E-Series,
Explorer 4.0L,
Explorer Sport
Trac 4.0L,
F-150 4.6L 2V,
F-Super Duty
6.8L,
Grand Marquis,
Mountaineer
4.0L,
Mustang 4.0L,
Mustang 5.4L,
Town Car		 - - GO to Pinpoint Test HH .
All others - - GO to Pinpoint Test HE .
RENDER: 1.0x

NO RELATED

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