P23F8Cylinder 7 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
- P23F8 identifies cylinder 7 and its injector B, so it needs at least seven cylinders, in practice a V8 or V10. Three V8 families using a pair of injectors in every cylinder are on record: Ford's 5.0 Coyote, which gained direct injection on top of port injection for the 2018 Mustang GT and F-150; Toyota's 2UR-GSE with D-4S in Lexus F models and the LC 500; and the supercharged GM LT5 in the 2019 Corvette ZR1, whose port injectors are driven by a separate fuel injection control module and listed as injector B (circuit codes from P21CF, Type A). None of them publishes P23F8; GM and Ford judge imbalance per bank. To narrow cylinder 7 down, use P21A2, the misfire code P0307 and the circuit code P21D5.
- What you may notice
- Check engine light on
- Fuel trim of one bank off while the other bank is normal
- Rarely a perceptible misfire
- Likely causes
- LikelyPort injector of cylinder 7 clogged or leaking
- PossibleIntake leak at cylinder 7
- RareFault in the separate injector B driver module, where fitted (e.g. GM LT5)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €120 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.