P3406 code meaning
Cylinder 1 Exhaust Valve Control Performance
Powertrain system Generic code P34xx codes Check engine light
What P3406 means
Where an engine controls the exhaust valves of cylinder 1 separately, P3406 would mean the exhaust side does not follow the command although the circuit checks pass. No manufacturer documents this code publicly. Ford holds a patent that detects an exhaust valve still opening after deactivation through pressure changes in the exhaust, and a GM patent, using one shared control valve, has the exhaust valves deactivate and also reactivate before the intake valves, so a lagging exhaust side is a real failure mode. Production systems from GM and Ford instead check the whole cylinder (GM P3498, Ford P3402). Electrical faults on this channel are P3405, P3407 and P3408; if the cylinder keeps pumping exhaust, the driver may feel roughness.
P3406 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 P3406
- Check engine lamp on
- Rough running or vibration in reduced-cylinder mode
- Cylinder deactivation suspended
Common causes of P3406
- PossibleInsufficient or degraded oil delays exhaust-side switching
- PossibleExhaust lifter or rocker of cylinder 1 not latching or unlatching
- Less likelyExhaust valve actuator 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 P3406 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). |
| 06 | The exact fault in that area. |
What to do next
- Note P3406 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 P3406
What does P3406 mean?
P3406 means "Cylinder 1 Exhaust Valve Control Performance". Where an engine controls the exhaust valves of cylinder 1 separately, P3406 would mean the exhaust side does not follow the command although the circuit checks pass. It is a generic code, so it means the same on every make.
Is it safe to drive with P3406?
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 P3406 fail an emissions test?
Yes, it can. P3406 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 P3406 to fix?
Difficulty: hard. A typical repair takes 0.5 to 12 hours of work. This is a job for a workshop.
Will P3406 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.