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

P24FD

Particulate Filter A Incorrect

The ECM identifies the installed particulate filter A as the wrong part — backpressure signature, regeneration efficiency or coded part-number do not match the application. Common after a non-OEM aftermarket DPF or a wrong-application replacement.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / FD

Possible causes

  • Incorrect or non-OEM DPF installed high
  • Coding mismatch after part replacement medium

Symptoms

  • Check engine light or DPF warning light on
  • Power loss / limp mode
  • Increased fuel consumption
  • Failed forced regeneration attempts

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 400–3000 €
  • Estimated time: 1–4 h
  • Component: particulate filter a
  • MIL / check engine light
  • emissions-relevant

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