OBD-II code · Powertrain (generic, extended)
P23FE Bank 1 System B Air-Fuel Ratio Imbalance
The secondary fuel system B on bank 1 (e.g. port-injection rail in a dual-injection engine, or LPG/CNG rail in a bi-fuel system) does not maintain calibrated mixture - lambda response on bank 1 is biased by an offset on the B system.
Is it safe to drive with P23FE?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySecondary fuel system has drifted
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 System B B1
Related codes
- P23FFBank 2 System 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
- P2400EVAP Leak Detection Pump Control Circuit Open
- P2401EVAP Leak Detection Pump Control Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.