P0446: the fuel vapour system's vent valve circuit has a fault
The evaporative emission system seals petrol vapour inside the fuel tank instead of letting it escape into the air, and a vent valve controls the system's one connection to outside air, which the engine control unit needs to open and close correctly to test the system for leaks. This code means the electrical circuit for that valve isn't behaving the way the computer expects. It covers the wiring, connector and valve together, without saying which one is at fault.
You might notice
- No symptom you'd feel while driving, beyond the engine warning light coming on
- evaporative emission system
- — seals petrol vapour inside the fuel tank instead of letting it escape into the air
What the code itself says
P0446 is a powertrain (engine, gearbox and drive system) code, and the 0 after the letter means it is a generic code with a standard meaning.
Grouped here as: Fuel vapour system — Catching fuel vapour from the tank and burning it off in the engine. That grouping is ours, to help explain the code. The code's official family is the letter at the start.
This page is generic. Your car isn't.
A code on its own only tells you what the sensor saw, not what's actually wrong — and that changes next to your other codes. Read this one together with the rest of your scan and we'll work out what's really going on.
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