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

P018F

Fuel System Over Pressure Relief Valve Frequent Activation

The mechanical pressure relief valve has activated repeatedly within a short window — pressure regulation is failing more than once.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 8F

Possible causes

  • Regulator intermittently sticking high

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 250–2000 €
  • Estimated time: 1–6 h
  • Component: pressure relief valve
  • Component: fuel pressure regulator
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required
  • limp mode possible

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