P3486Cylinder 11 Exhaust Valve Control 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
- P3486 flags a functional problem with the exhaust valve of cylinder 11: the circuit is healthy, but the valve does not reach the commanded state. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. With a twelve-cylinder engine the consequences of a valve that keeps opening are that the cylinder pumps cold air through the exhaust and the converter cools, the issue Bentley avoids on its W12 by alternating banks. A Ford patent shows how such a leaking exhaust valve can be spotted from exhaust pressure. The reverse fault, a valve that stays shut, compresses trapped gas when the cylinder returns. As none of the known V12 or W12 systems switches valves individually, there is no documented user. P3485, P3487 and P3488 are the electrical faults.
- What you may notice
- Check engine lamp on
- Knock when cylinder 11 reactivates
- Misfire on cylinder 11 (P0311)
- Likely causes
- PossibleExhaust switching element of cylinder 11 jammed
- PossibleOil supply inadequate for exhaust switching
- RareExhaust actuator slow to respond
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.