OBD-II code · Powertrain (manufacturer / generic)

P3412 Cylinder 2 Deactivation Stuck Off

The engine control module has detected that cylinder 2 deactivation hardware is stuck in the off state. The deactivation cannot be released when full-cylinder operation is commanded.

Is it safe to drive with P3412?

Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.

Common causes

  • Most likelyLifter stuck collapsed
  • PossibleSolenoid stuck
  • Less likelyCarbon or debris buildup preventing free movement

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
2–10 h
Emissions test
Likely to fail
After the fix
A drive cycle is needed before the light stays off
Parts involved
Cylinder Deactivation Solenoid, Lifter

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.