P219CCylinder 1 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
- P219C names cylinder 1 as the one whose mixture departs from the others. Not every system can do that: CARB lets the stored code point only as far as the monitoring method allows, so many engines just log P219A or P219B. Those that resolve single cylinders include Toyota (the 2014 Corolla 2ZR gained P219C to P219F) and VW, whose 2014 2.5 litre five-cylinder leans each cylinder in turn and judges the resulting roughness, flagging a ratio below 0.19 or above 1.50. Subaru reflashed 2019 to 2020 Crosstrek Hybrid ECMs because P219C to P219F set without a real fault. Where the fault is real, check the cylinder 1 injector, its intake port seal and valve tightness with a leak-down test, as Toyota prescribes for the 2015 Tacoma V6. Cylinder numbering differs between makers, so confirm which cylinder is number 1.
- What you may notice
- Check engine light on
- Often no noticeable symptom
- Possible P0301 or rough idle if cylinder 1 deviates strongly
- Likely causes
- LikelyCylinder 1 injector clogged, leaking or out of tolerance
- PossibleValve leakage on cylinder 1 (leak-down test)
- PossibleIntake runner or injector seal leak at cylinder 1
- RareFalse detection fixed by ECM reprogramming (e.g. Subaru Crosstrek Hybrid)
- 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.