P3426 code meaning
Cylinder 4 Deactivation/Intake Valve Control Performance
Powertrain system Generic code P34xx codes Check engine light
What P3426 means
P3426 is one of the few performance codes in this range that makers really use. FCA calls it Cylinder 4 Deactivation Control Performance on the 6.4 l Heavy Duty Hemi with MDS; bulletins 18-082-16 and 18-036-20 list it with P3402, P3442 and P3450 and fix it with new PCM software. Ford stores it on the 2025 F-150 5.0 l: bulletin 25-2487, replaced by 26-2093, traces P3402 and P3426 to a restricted oil feed tube for the right-bank deactivation solenoids, which is replaced under the valve cover. GM checks cylinder 4 mechanically under P349B instead. Circuit faults are P3425, P3427 and P3428. The lamp comes on, and the engine may run rough or stay in full-cylinder mode.
P3426 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 12 hours
- Clears after repairAfter a drive cycle
Symptoms of P3426
- Check engine lamp on
- Misfire on cylinder 4 or rough running
- Drone or shudder at light throttle
Common causes of P3426
- Most likelyRestricted oil feed tube to the deactivation solenoids (Ford 5.0 l, TSB 26-2093)
- PossibleControl software needing an update (FCA 6.4 l Hemi)
- PossibleLow or worn-out engine oil
- Less likelyDeactivating lifter of cylinder 4 sticking
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder deactivation solenoidLifterEngine oil
What each part of P3426 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 3 | Mixed range: generic and manufacturer-specific codes. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 26 | The exact fault in that area. |
What to do next
- Note P3426 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P3426
What does P3426 mean?
P3426 means "Cylinder 4 Deactivation/Intake Valve Control Performance". P3426 is one of the few performance codes in this range that makers really use. It is a generic code, so it means the same on every make.
Is it safe to drive with P3426?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P3426 fail an emissions test?
Yes, it can. P3426 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P3426 to fix?
Difficulty: hard. A typical repair takes 0.5 to 12 hours of work. This is a job for a workshop.
Will P3426 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.