Powertrain, generic (extended)

P23F6 Cylinder 5 Injector B Air-Fuel Ratio Imbalance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P23F6 flags cylinder 5 and is the first code in this row that a four-cylinder engine can never set. Engines with port plus direct injection and at least five cylinders are mostly V6 and V8 units: Ford's second-generation 3.5 EcoBoost V6, first shown in the 2017 Ford GT, Toyota's 2GR-FKS V6 with D-4S, and the V8s named at P23F8. On the Lamborghini Huracán V10, which combines direct and multi-point injection, cylinder 5 closes the first group of five. The code means the trim of that single cylinder points to its injector B, which in these designs is the port injector. Nobody publishes P23F6 with a threshold. Confirm the maker's numbering, then compare P21A0 and the misfire counter P0305 before replacing the injector.

Likely causes

Port injector of cylinder 5 out of tolerance

Intake manifold gasket leaking near cylinder 5

Intermittent contact in the injector B wiring of cylinder 5 (P21D3)

Symptoms

Check engine light on
Usually no change in performance
Fuel trim of the affected bank drifts

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€100–900

Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel injector b cyl 5

References: law.cornell.edu, en.wikipedia.org, en.wikipedia.org, en.wikipedia.org.