OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P25AA

Piston Cooling Oil Control Circuit Low

The piston-cooling oil-jet control circuit reads stuck low — short to ground or low-side driver stuck on. The jets may be enabled continuously, raising oil pump load and lowering oil pressure to other consumers.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / AA

Possible causes

  • Control wire shorted to ground high
  • Connector pins corroded - high contact resistance low
  • Harness chafing through insulation low

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 200–1200 €
  • Estimated time: 1–4 h
  • Component: piston cooling solenoid
  • MIL / check engine light

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication