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

P04B0

Refueling Vapor Control Valve Circuit Open

The refueling vapor control valve - typically part of the ORVR or capless fueling system - has an open control circuit. The valve directs fuel vapor from the tank into the canister during refueling and must open when the fuel filler is opened. Without it, vapor escapes during refueling and the system fails leak diagnostics.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / B0

Possible causes

  • Open in harness or solenoid winding 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: 120–400 €
  • Estimated time: 0.8–1.8 h
  • Component: refueling vapor valve
  • Component: vapor canister
  • Component: fuel filler assembly
  • 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