OBD-II code · Powertrain (manufacturer / generic)

P3457 Cylinder 7 Deactivation

The engine control module has detected a fault in the cylinder 7 deactivation system. Cylinder 7 cannot reliably switch between active and deactivated state.

Is it safe to drive with P3457?

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

Common causes

  • Most likelyDeactivation solenoid failed
  • PossibleLifter stuck

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, Engine Wiring Harness

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