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

P2420

EVAP Switching Valve Stuck Closed

The EVAP switching valve cannot open when commanded. Purge or test flow cannot reach the appropriate path and the leak monitor aborts.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / 20

Possible causes

  • Valve stuck closed mechanically high
  • Drive circuit open medium
  • Carbon or debris buildup preventing free movement low

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: 60–400 €
  • Estimated time: 0.5–2 h
  • Component: evap switching valve
  • 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