OBD-II code · Powertrain (generic, extended)
P23FA Cylinder 9 Injector B Air-Fuel Ratio Imbalance
On dual-injector systems (typical for some heavy-duty diesels and some petrol/gas bi-fuel applications) the secondary injector B at cylinder 9 cannot keep its mixture in balance with the rest of the bank.
Is it safe to drive with P23FA?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyInjector B for cylinder 9 has drifted in flow rate
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Fuel Injector B Cyl 9
Related codes
- P23F2Cylinder 1 Injector B Air-Fuel Ratio Imbalance
- P23F3Cylinder 2 Injector B Air-Fuel Ratio Imbalance
- P23F4Cylinder 3 Injector B Air-Fuel Ratio Imbalance
- P23F5Cylinder 4 Injector B Air-Fuel Ratio Imbalance
- P23F6Cylinder 5 Injector B Air-Fuel Ratio Imbalance
- P23F7Cylinder 6 Injector B Air-Fuel Ratio Imbalance
- P23F8Cylinder 7 Injector B Air-Fuel Ratio Imbalance
- P23F9Cylinder 8 Injector B Air-Fuel Ratio Imbalance
- P23FBCylinder 10 Injector B Air-Fuel Ratio Imbalance
- P23FCCylinder 11 Injector B Air-Fuel Ratio Imbalance
- P23FDCylinder 12 Injector B Air-Fuel Ratio Imbalance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.