OBD-II code · Powertrain (generic, extended)
P23FF Bank 2 System B Air-Fuel Ratio Imbalance
The secondary fuel system B on bank 2 (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 2 is biased by an offset on the B system.
Is it safe to drive with P23FF?
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 B2
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.