2021 Ford Bronco Base, 4D Utility, 2.3L Eng VIN H, Part Time T/Case ControlFACTORY OEM SERVICE PROCEDURE

P0174 - System Too Lean Bank 2

DTC DESCRIPTION P0174 - SYSTEM TOO LEAN BANK 2

Description:  The adaptive fuel strategy continuously monitors the fuel delivery hardware. This DTC sets when the adaptive fuel tables reach a rich calibrated limit. Refer to Powertrain Control Software, Fuel Trim for additional information.
Possible Causes: 
  • Ethanol content in the fuel
  • Fuel filter restricted or dirty
  • Damaged or worn fuel pump
  • Leaking fuel pump check valve
  • Leaking or contaminated fuel injectors
  • Low fuel pressure or running out of fuel
  • EVAP purge valve is leaking when the canister is clean
  • Fuel supply line restricted
  • Fuel rail pressure (FRP) sensor bias
  • Exhaust leaks in the exhaust manifold gasket or mating gaskets before or near the heated oxygen sensor (HO2S)
  • Air leaks after the mass airflow (MAF) sensor (if equipped)
  • Vacuum leaks
  • Positive crankcase ventilation (PCV) system is leaking or the valve is stuck open
  • Incorrectly seated engine oil level indicator
  • Intake air turbulence due to incorrect air filter
  • Contaminated MAF sensor (if equipped)
  • Damaged MAF sensor (if equipped)
Diagnostic Aids:  View the freeze frame data to determine the operating conditions when the DTC was set. Observe the LONGFT1 and LONGFT2 PIDs. Refer to Adaptive Fuel Diagnostic Trouble Code (DTC) Diagnostic Techniques, for additional information and the appropriate pinpoint test for specific concern identification.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test H.
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