P0447 code meaning
EVAP System Vent Control Circuit Open
Powertrain system Generic code P04xx codes Check engine light
What P0447 means
The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. P0447 belongs to the older scheme for the vent valve circuit (P0446 circuit, P0447 open, P0448 shorted), used by Subaru (also in the Saab 9-2X), VW and Nissan; GM reports an open vent circuit as P0449, Ford as P0446. On Subaru the valve is fed from the main relay and switched to ground by the module; if the voltage at the module output is missing or the coil is high-resistance (nominal 10–100 Ω), the code sets after two consecutive drives. The valve stays in its rest position and the leak test cannot run.
P0447 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0447
- Check engine light on
- EVAP leak test does not run, readiness not set
- Usually no change in driving
Common causes of P0447
- Most likelyVent valve connector corroded or off (underbody, splash water)
- PossibleVent valve coil open (resistance outside 10–100 Ω)
- PossibleWire to the module or supply from the main relay open
- Less likelyEngine module or its connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EVAP vent valveVent valve wiringEngine control module
What each part of P0447 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 47 | The exact fault in that area. |
What to do next
- Note P0447 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0447
What does P0447 mean?
P0447 means "EVAP System Vent Control Circuit Open". The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. It is a generic code, so it means the same on every make.
Is it safe to drive with P0447?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0447 fail an emissions test?
Yes, it can. P0447 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0447 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0447 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.