P3418 code meaning
Cylinder 3 Deactivation/Intake Valve Control Performance
Powertrain system Generic code P34xx codes Check engine light
What P3418 means
P3418 is meant for a cylinder 3 deactivation that is wired correctly yet does not respond as requested: the cylinder keeps breathing when it should rest, or fails to come back. No manufacturer documents this code publicly. GM tests the hardware of cylinder 3 under its own code P349A; bulletin 20-NA-204 for the 2021 L84 and L87 notes that a voltage dip during cranking can briefly disable the outputs and set that code without a real fault. Honda shows the same failure pattern in another form: in bulletin 13-055 excess cold-start oil pressure pushed cylinders 1 to 4 into cut mode uncommanded, logged as P3400/P3497 with misfires. Circuit faults belong to P3417, P3419 and P3420. Expect rough running and a misfire code.
P3418 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 P3418
- Misfire code for cylinder 3 (P0303)
- Shudder when the engine changes between modes
- Check engine lamp on
Common causes of P3418
- Most likelyLow oil level, wrong viscosity or aged oil
- PossibleLifter or rocker of cylinder 3 not locking or unlocking
- PossibleCylinder 3 control valve sticking or its screen blocked
- Less likelyOil pressure too high or too low for the switching window
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 P3418 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). |
| 18 | The exact fault in that area. |
What to do next
- Note P3418 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 P3418
What does P3418 mean?
P3418 means "Cylinder 3 Deactivation/Intake Valve Control Performance". P3418 is meant for a cylinder 3 deactivation that is wired correctly yet does not respond as requested: the cylinder keeps breathing when it should rest, or fails to come back. It is a generic code, so it means the same on every make.
Is it safe to drive with P3418?
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 P3418 fail an emissions test?
Yes, it can. P3418 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 P3418 to fix?
Difficulty: hard. A typical repair takes 0.5 to 12 hours of work. This is a job for a workshop.
Will P3418 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.