P3430Cylinder 4 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
- P3430 would cover exhaust valves on cylinder 4 that keep opening, or stay shut, against the command while the circuit itself is sound. No manufacturer documents this code publicly. Ford shows both sides of the problem: a Ford patent recognises an exhaust valve opening after shutdown from changes in exhaust pressure and responds by reactivating the cylinder and storing a code, while in practice the 2025 F-150 5.0 l reports a cylinder 4 switching fault as P3426 and traces it to a restricted solenoid oil feed tube (bulletin 26-2093). An exhaust valve that does not stay closed lets fresh air reach the catalyst and the oxygen sensors, which can show up as fuel trim errors, misfire counts and vibration.
- What you may notice
- Vibration in reduced-cylinder mode
- Lean or rich fuel trim codes
- Check engine lamp on
- Likely causes
- PossibleRestricted oil supply to the cylinder 4 switching elements
- PossibleExhaust lifter or rocker of cylinder 4 not changing state
- RareOil too thin, too old or too low
- 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.