P3470Cylinder 9 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
- P3470 covers a cylinder 9 exhaust valve that does not follow its deactivation command although the control circuit shows no electrical fault. No manufacturer documents this code publicly; J2012 reserves the codes for cylinders 9 to 12 for engines with more than eight cylinders. The risk behind it is described in a Ford patent: an exhaust valve that keeps opening after shut-off spoils the gas cushion in the cylinder and can be detected from changes in exhaust pressure. The opposite case, a valve that stays shut on reactivation, traps hot gas under pressure. Neither the Lamborghini Aventador V12 nor the Huracán V10 publishes how their bank shut-off works, and Audi's V10 simply cuts injection and ignition, so this check has no known user. Electrical faults of the same actuator: P3469, P3471, P3472.
- What you may notice
- Check engine lamp on
- Knock or jolt when cylinder 9 comes back in
- Misfire on cylinder 9 (P0309)
- Likely causes
- PossibleExhaust switching element of cylinder 9 stuck
- PossibleInsufficient oil pressure for the exhaust switch
- RareExhaust actuator sluggish
- 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.