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

P05F3

Exhaust Aftertreatment Power Relay Control Circuit Open

The power relay that supplies the entire exhaust aftertreatment system (DOC, DPF, SCR sensors and heaters) reports an open control circuit. Aftertreatment effectively goes offline.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / F3

Possible causes

  • Open in relay control or harness high
  • Pin pushed back out of connector body low
  • Cracked solder joint inside the module or sensor low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–350 €
  • Estimated time: 0.5–1.8 h
  • Component: aftertreatment power relay
  • 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