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

P24A1

Closed Loop Particulate Filter Regeneration Control At Limit Temperature Too High

Same as P24A0 with the controller fully reducing heat input yet EGT still rising - typical for a runaway exotherm in the DPF (oil contamination).

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / A1

Possible causes

  • DPF runaway exotherm high

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: 400–3500 €
  • Estimated time: 2–8 h
  • Component: dpf b1
  • 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