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Home >> Mercury >> 2009 >> Mariner Base, 2.5 7, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Powertrain DTC Charts & Descriptions (Except Diesel & Hybrid) >> DTC Diagnosis >> DTC P0400: - Exhaust Gas RECIRCULATION (EGR) Flow

DTC P0400: - Exhaust Gas RECIRCULATION (EGR) Flow

DTC P0400: - EXHAUST GAS RECIRCULATION (EGR) FLOW

Description:  The electric EGR (EEGR) system is monitored once per drive cycle at high and low load conditions. The test fails when a concern is detected by powertrain control module (PCM) calculations indicating the EGR flow is less or greater than expected.
Possible Causes: 
  • EEGR valve stuck open or closed
  • Connector to EEGR not seated
  • EEGR motor winding circuits short or open
  • No voltage to the EEGR
  • Harness open or short to voltage or ground
  • Vacuum signal to manifold absolute pressure (MAP) restricted or leaking
  • Mass air flow (MAF) sensor signal erroneous
  • Carbon build up in the EEGR valve seat area
  • One or more sensors is not responding or is out of range
Diagnostic Aids:  All of the following sensors input data to the PCM for correct operation of the EEGR system: engine coolant temperature (ECT), crankshaft position (CKP), intake air temperature (IAT), MAF, throttle position (TP), MAP. Any DTC relating to these sensors must be resolved prior to addressing DTC P0400.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test KD .