P23F3
Cylinder 2 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 2 cannot keep its mixture in balance with the rest of the bank.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Injector B for cylinder 2 has drifted in flow rateCommon
Parts involved
- Fuel Injector B Cyl 2
P23F3 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.