OBD-II code · Powertrain (generic, extended)
P25AC Piston Cooling Oil Control Circuit Performance/Stuck Off
The control circuit is electrically intact, but the solenoid valve does not open when commanded — confirmed by oil-pressure or oil-temperature feedback that does not change after the activation pulse. Piston cooling does not engage under high load — risk of piston-crown overheating and ring-land cracks.
Is it safe to drive with P25AC?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySolenoid stuck closed by oil sludge
- 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.