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

P04F0

EVAP System High Load Purge Line A Performance

On engines that have a separate high-load purge line - to use boost pressure to pull vapor on turbo applications - the ECU monitors flow when this path is commanded. The flow is below the expected level - the venturi, line, or check valve is restricted, or the line is incorrectly routed.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / F0

Possible causes

  • Line, venturi or check valve restricted high

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: medium
  • DIY: possible
  • Estimated cost: 120–450 €
  • Estimated time: 0.8–2 h
  • Component: evap high load purge line a
  • Component: evap purge venturi
  • Component: evap check valve
  • 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