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

P2459

Diesel Particulate Filter Regeneration Frequency

Active DPF regenerations are being requested more often than the calibration window allows. Indicates that soot accumulates faster than the filter can burn it off — typically due to short-trip use, leaking injectors, or excessive engine oil consumption.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / 59

Possible causes

  • Predominantly short-trip operation high
  • Leaking injector raises soot output medium
  • High engine oil consumption (turbo seals, valve stems) medium

Symptoms

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

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 100–1500 €
  • Estimated time: 1–6 h
  • Component: diesel particulate filter
  • Component: fuel injector
  • Component: turbocharger
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

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