OBD-II code · Powertrain (generic, extended)

P25AD Piston Cooling Oil Control Circuit Stuck On

The piston cooling solenoid does not close when commanded off — jets remain active when not needed. Oil pressure to top-end consumers may sag, and warm-up takes longer because the cooling jets remove heat from the pistons during cold start.

Is it safe to drive with P25AD?

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

Common causes

  • Most likelySolenoid stuck open
  • Less likelyCarbon or debris buildup preventing free movement
  • Less likelyComponent wear with age - mechanical play

Repair at a glance

Difficulty
Hard
DIY friendly
Best left to a mechanic
Typical labour
1.5–5 h
Emissions test
Usually unaffected
Parts involved
Piston Cooling Solenoid

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