P219FCylinder 4 Air-Fuel Ratio Imbalance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P219F singles out cylinder 4, the last cylinder on four-cylinder engines. Infiniti issued a bulletin for 2017 to 2018 QX60 with the direct-injection VQ35DD that stored only P219F without any driveability complaint; the remedy was ECM reprogramming followed by the idle air volume learn. Honda found the opposite case on 2023 to 2025 CR-V Hybrid and Accord Hybrid: a leaking injector made the mixture rich, fouled spark plugs and caused rattling and rough running, with P219C to P219F, P0172 and A/F sensor heater codes; all injectors and the fouled plugs were replaced and Honda warned against changing the A/F sensor first. Hyundai's 2018 Sonata 2.0 turbo also set P219F through software. Reading the spark plug of the flagged cylinder is a quick first check for rich or lean burning.
- What you may notice
- Check engine light on
- Rough running or rattling noise when an injector leaks
- No symptom when the cause is software
- Likely causes
- LikelyLeaking injector at cylinder 4
- PossibleOversensitive detection fixed by ECM reprogramming (e.g. Infiniti QX60, Hyundai Sonata)
- RareFouled spark plug as a consequence of a rich cylinder
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.