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P0401 - EGR A Flow Insufficient Detected

DTC DESCRIPTION P0401 - EGR A FLOW INSUFFICIENT DETECTED

Description:  The exhaust gas recirculation (EGR) system is monitored during steady state driving conditions while the EGR is commanded on. This DTC sets when the signal from the differential pressure feedback EGR sensor indicates that EGR flow is less than the desired minimum.
Possible Causes: 
  • EGR flow path restricted
  • VREF circuit open
  • SIGRTN circuit open
  • Differential pressure feedback EGR sensor downstream hose is off or restricted
  • Differential pressure feedback EGR sensor hoses are both off
  • Differential pressure feedback EGR sensor hoses are reversed
  • Damaged EGR orifice tube
Diagnostic Aids:   
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test HE.
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