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

P25BD

Unmetered Fuel - Forced Engine Shutdown

The engine controller commanded a forced shutdown after detecting unmetered fuel reaching the combustion chambers. Common on diesels with leaking turbo seals or cracked intercoolers that drip oil into the intake — the engine then runs on the oil and can overspeed.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / BD

Possible causes

  • Turbocharger oil seal leak feeds engine oil into the intake high
  • Oil collected in the intercooler is sucked into the engine on load medium
  • Failed PCV / crankcase breather floods intake with oil mist medium

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 400–4000 €
  • Estimated time: 3–10 h
  • Component: turbocharger seals
  • Component: intercooler
  • Component: intake manifold
  • Component: air shutoff valve
  • 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