P34A1Cylinder 10 Deactivation/Intake Valve Performance
- 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
- P34A1 would mean that cylinder 10 kept opening its valves while it was supposed to be deactivated. No manufacturer documents this code publicly; it only makes sense on V10, V12 or W12 engines. Lamborghini, for instance, gave the Aventador LP 700-4 a Cylinder Deactivation System that rests one bank at speeds under 135 km/h, but no public diagnostic table lists P34A1. The physics of a check is shared with smaller engines: Ford's patent US8667835B2 watches the rise and fall of manifold pressure across successive intake events and compares it with the commanded pattern. Causes would mirror those of the V8 codes P3498 to P349F: a stuck switching element, a faulty oil control valve or poor oil. P3474 covers the control side of cylinder 10.
- What you may notice
- Check engine lamp on
- Reduced-cylinder mode no longer offered
- Uneven running at low load
- Likely causes
- LikelySwitching element of cylinder 10 not unlocking
- PossibleDeactivation oil control valve sticking
- PossibleOil level too low or oil aged
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.