Home › Fault Codes › Cars & OBD › Standard › P0446
P0446

Evaporative emission control system vent control circuit malfunction

The ECU has detected a fault in the electrical control circuit for the EVAP vent valve.

What this code means

The ECU has detected a fault in the electrical control circuit for the EVAP vent valve.

Possible causes

  • Failed vent valve or solenoid
  • Damaged wiring or connector
  • Blocked vent path
  • Control-module driver fault

Common symptoms

  • Check engine light
  • Usually no obvious driveability symptoms
  • Possible emissions-test failure

Checks to make

  1. Inspect vent-valve wiring and connector
  2. Check vent valve operation
  3. Inspect vent/filter path for blockage

Safety

  • Do not replace parts from the code alone. Confirm the fault with live data, wiring checks and manufacturer procedures. Keep clear of hot or moving engine components.

Model notes

The code definition is generic; exact diagnostic thresholds, component locations and repair procedures vary by vehicle.