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

P05EB

Cold Start SCR NOx Catalyst Inlet Temperature Too Low

Same as P22FF but specifically during the cold-start window - the SCR catalyst inlet temperature does not reach the threshold needed for NOx reduction in the cold-start phase, so reductant injection cannot be enabled.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / EB

Possible causes

  • Heat-up strategy not bringing exhaust to temp high

Symptoms

  • Check engine light on
  • Failed emissions inspection
  • Possibly slightly increased fuel consumption
  • Sulfur (rotten egg) smell from exhaust under load

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–800 €
  • Estimated time: 1–3 h
  • Component: scr inlet temperature sensor
  • Component: scr catalyst
  • Component: exhaust heat management
  • 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