P23F2Cylinder 1 Injector B Air-Fuel Ratio Imbalance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P23F2 says that the mixture in cylinder 1 has drifted away from the other cylinders and that the control unit holds the second injector of that cylinder, injector B, responsible. Only engines that feed each cylinder through two injectors can produce it. Toyota first paired a port and a direct injector in each cylinder with D-4S on the 2005 2GR-FSE V6. Ford's 2024 OBD summary shows what the letter means there: the port injectors are checked as Fuel System B (circuit codes P21CF to P21D6), the direct injectors as system A. CARB makes an imbalance check mandatory and asks that the code name the cause as exactly as the method permits. No maker documents P23F2 itself; Ford and GM still report imbalance per bank. Cylinder 1 is by definition on bank 1, so read P219C and P0301 alongside.
- What you may notice
- Check engine light on
- Often no noticeable drivability change
- Slightly rough idle or a misfire count on cylinder 1
- Likely causes
- LikelyInjector B (usually the port injector) of cylinder 1 clogged or dripping
- PossibleLeaking injector O-ring or intake runner gasket at cylinder 1
- RareLoose connector on injector B of cylinder 1 (often with P21CF)
- RarePoor valve sealing on cylinder 1
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.