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

P2585

Fuel Additive Control Module Warning Lamp Request

The fuel additive control module asks for the additive-low warning lamp to be illuminated — the additive tank (Eolys/Cerine, used to lower DPF regen temperature) is approaching empty or has reached a service threshold. Continued driving without refilling will eventually disable DPF regeneration.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 85

Possible causes

  • Additive tank low — service refill required high

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 80–350 €
  • Estimated time: 0.5–1.5 h
  • Component: fuel additive tank

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