Powertrain, generic (extended)

P23FF Bank 2 System B Air-Fuel Ratio Imbalance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P23FF mirrors P23FE for bank 2 and can only occur on V, W or boxer engines, because inline engines have no second bank. It means the cylinders on the side without cylinder 1 deviate from each other and the fault is assigned to injection system B, which on Ford's PFDI engines is the port path (lean and rich codes P2BF2/P2BF3). Bank-level monitors on such engines are documented, but under the general codes: GM's 2019 LT5 Corvette V8 fails bank 2 when the normalised oxygen sensor ratio exceeds 0.75, rated Type A and lighting the MIL on the first failed trip, and Ford sets P219B. No manufacturer publishes P23FF. When the fault stays confined to bank 2, the culprit usually sits on that side, such as a port fuel rail, a manifold gasket or several injectors of that bank.

Likely causes

Several port injectors on bank 2 with deposits or wear
Intake manifold gasket leaking on bank 2
Supply problem in the port fuel rail feeding bank 2
Front oxygen sensor or its wiring on bank 2 distorting the signal

Symptoms

  • Check engine light on
  • Fuel trims of the two banks clearly apart
  • Possibly P2BF2 or P2BF3 as well

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 b2

Related codes

P219BP23FEP2BF2P2BF3P23F9

References: fordservicecontent.com, gsi.ext.gm.com, law.cornell.edu.