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Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Powertrain DTC Charts & Descriptions (Except Diesel & Hybrid) >> DTC Diagnosis >> DTC P0406: - Exhaust Gas RECIRCULATION (EGR) Sensor A Circuit High

DTC P0406: - Exhaust Gas RECIRCULATION (EGR) Sensor A Circuit High

DTC P0406: - EXHAUST GAS RECIRCULATION (EGR) SENSOR A CIRCUIT HIGH

Description:  The EGR monitor checks the EGR sensor signal to the powertrain control module (PCM) for high voltage. The test fails when the average voltage to the PCM exceeds the maximum calibrated value.
Possible Causes: 
  • Differential pressure feedback EGR circuit open
  • VREF circuit short to voltage
  • Damaged differential pressure feedback EGR sensor.
  • Differential pressure feedback EGR circuit short to voltage
  • SIG RTN circuit open
Diagnostic Aids:  A DPFEGR PID reading greater than 4.5 volts with the ignition ON, engine OFF or running indicates a hard fault.
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 .