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

P0455

Evaporative Emission System Leak Detected (Large Leak)

A large leak has been detected during the EVAP system pressure or vacuum test — large enough that the system cannot hold pressure for the diagnostic interval. Typically a missing fuel cap, disconnected hose, or split canister.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 55

Possible causes

  • Fuel cap missing or not seated high
  • EVAP hose disconnected high
  • Charcoal canister cracked medium

Symptoms

  • Check engine light on
  • Possible smell of fuel near tank or engine bay
  • Failed emissions inspection
  • Loose-cap warning may appear

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 10–350 €
  • Estimated time: 0.1–2.5 h
  • Component: fuel filler cap
  • Component: evap canister
  • Component: evap hose
  • 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