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P0446: EVAP vent control circuit malfunction

The ECU sees an electrical fault in the valve that lets the vapour canister breathe. Typically a dirty or wet connector, or the valve itself.

Code P0446 at a glance
CodeP0446
SystemEngine and transmission
GroupP04xx, Emissions control
TypeGeneric: it means the same on every make
Can you keep driving?Yes, no rush

What P0446 means

The vent valve opens the canister to outside air and closes it when the ECU wants to test for leaks. It usually sits by the canister near the tank, where it gets water and dirt. The ECU has found a problem in its electrical circuit.

Most common causes

  • Dirty, corroded or wet valve connector
  • Damaged wiring under the car
  • Faulty vent valve or one jammed with dirt
  • Fuse or power supply to the circuit
  • ECU fault (rare)

Symptoms

  • Engine warning light on
  • Fuel pump nozzle keeps clicking off or the tank is hard to fill
  • Other EVAP codes at the same time
  • Often no symptoms

Can you drive with P0446?

Yes, no rush It does not affect driving. You can use the car normally and fix it when convenient.

How to check it

If the nozzle keeps clicking off when you refuel, that points to a vent valve stuck closed. Look under the car by the canister to see whether the valve connector is full of mud or corrosion.

How to read and clear P0446 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0446 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0446 is a generic code, so it means the same on any make, for example on Alfa Romeo, Cupra, Dacia, Jeep, Nissan, Škoda. See what Final OBD does on your car in makes and models.

What does code P0446 mean?

The vent valve opens the canister to outside air and closes it when the ECU wants to test for leaks. It usually sits by the canister near the tank, where it gets water and dirt. The ECU has found a problem in its electrical circuit.

Can you drive with P0446?

It does not affect driving. You can use the car normally and fix it when convenient.

How do you clear P0446?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0446 comes back.