Powertrain, generic (extended)

P23FE Bank 1 System B Air-Fuel Ratio Imbalance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P23FE reports a cylinder-to-cylinder imbalance on bank 1 that the control unit attributes to fuel system B, without naming a cylinder. Ford's 2024 OBD summary explains the letter for its dual-injection engines: the port path is Fuel Control System B with its own lean and rich codes (P2BF0/P2BF1 for bank 1), while direct injection forms system A. Ford's imbalance monitor itself still stores only P219A: it runs once per trip in closed loop after the fuel monitor has adapted, needs 300 to 700 s and fails above an imbalance ratio of 0.75. No manufacturer publishes P23FE. An inline engine has only bank 1, so the code then covers all its cylinders; on V engines it is the side with cylinder 1. A system-wide B code points to the port rail, its pressure or several port injectors at once.

Likely causes

Several port injectors on bank 1 fouled by deposits
Port fuel rail pressure or low-pressure supply wrong on bank 1
Intake manifold leak on the bank 1 side
Front oxygen sensor of bank 1 responding poorly

Symptoms

  • Check engine light on
  • Lean or rich fuel trim on bank 1, possibly P2BF0 or P2BF1
  • Slightly increased fuel consumption

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,200
Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel system b b1

Related codes

P219AP23FFP2BF0P2BF1P23F2

References: fordservicecontent.com, law.cornell.edu.