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

P04EC

EVAP System Large Leak Detected Fuel Tank Side

Same as P04EA but the leak is large enough that the system cannot build the test pressure or vacuum at all - typically a missing fuel cap, an unseated hose or a torn vapor line on the tank side.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / EC

Possible causes

  • Fuel cap missing or not seated high
  • Vapor hose pulled off or torn 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: 25–300 €
  • Estimated time: 0.2–1.5 h
  • Component: fuel cap
  • Component: evap hose tank side
  • 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