P0447: Evaporative Emission System Vent Control Circuit Open
Key takeaways
- P0447 means the engine computer sees an open circuit where the EVAP vent valve should be: no current flows when it tries to close the valve.
- It's an emissions fault, so the car is safe to drive, but it will fail an OBD emissions inspection.
- A broken wire or corroded connector near the tank, a blown fuse and a vent valve with a burned-out coil are the usual causes.
- Most P0447 repairs at a US independent shop run $100–$350; on cars where the vent valve is built into the charcoal canister, the repair can reach $800.
What P0447 means
The engine computer tried to work the valve that lets your fuel-vapor canister breathe, and found a break in its electrical circuit.
Scanners call it Evaporative Emission System Vent Control Circuit Open. The vent valve sits between the charcoal canister and fresh air. It stays open most of the time so the tank can breathe, and the computer closes it to seal the EVAP system for a leak test. The computer watches the voltage on the valve’s control wire. If that voltage says no current can flow, as with a cut wire, an unplugged connector or a burned-out coil, it sets P0447. It’s the more specific cousin of P0446, which covers the vent circuit in general.
Is it safe to drive?
Yes. A vent circuit fault doesn’t change how the engine runs. With the valve dead, it usually sits open, so the tank still breathes and fill-ups stay normal. You’ll fail an OBD emissions inspection with the light on, and the EVAP leak test can’t run until it’s fixed.
What changes the answer: a strong raw-gas smell around the car or in the cabin. That’s a real fuel leak, not a circuit fault, and it needs a look before you keep driving. See car smells like gas.
Causes, ranked
| Cause | How you confirm it | Typical cost (US independent shop, 2026) |
|---|---|---|
| Broken wire or corroded connector near the tank | Green corrosion or a cracked plug at the valve; no power or no control signal at the plug | $100–$250 |
| Vent valve coil burned out | Power and control reach the plug, but the coil reads open on a meter and the valve doesn’t click | $120–$350 |
| Blown fuse for the EVAP circuit | Fuse check; valve has no power at all | $0–$20 |
| Vent valve built into the canister assembly (some makes) | Coil reads open, and the valve isn’t sold separately | $300–$800 |
| Harness damaged by road debris or rubbing | Chafed wire along the frame rail or near the tank straps | $100–$250 |
What to check first
- The EVAP fuse. Find it in the owner’s manual fuse chart. A blown fuse is the cheapest answer, but find out why it blew before driving off.
- Look at the valve connector. It’s usually near the tank or the canister, under the rear of the car, right where road water and salt land. A plug that’s corroded, cracked or hanging loose is a common find.
- Measure the coil. With the connector off, a meter across the valve’s two pins should read a few ohms to a few dozen. An open reading means the valve is dead.
- Command the valve. A shop with a bidirectional scan tool can click the valve and check power and control at the plug. That separates the valve from the wiring in a few minutes.
- Check bulletins. The only pattern in NHTSA’s files is Jaguar: bulletins for the 2010–2015 XJ list P0447 among a group of EVAP codes and blame water or ice from tire spray trapped in the leak-check pump module near the tank. On other makes, test before buying parts.
- Clear it and drive. After a repair, clear the code and drive for a few days. The EVAP test only runs under certain conditions, so give it time.
The engine computer’s own driver can fail, but that’s rare; rule out everything above first.
What it costs
The cheap outcome is a fuse, under $20. The common outcome is a connector or wiring repair at $100–$250, or a vent valve at $120–$350. The expensive outcome is a vent valve that only comes with the charcoal canister, $300–$800. A ten-minute coil and wiring test is what keeps you from paying for a valve when a corroded plug was the problem.
Related codes
P0447 often travels with P0446 and with P0449, the vent valve solenoid circuit. P0448 is the same circuit shorted instead of open. Leak codes like P0442 or P0455 can set at the same time because the system can’t be sealed for its test; fix the circuit first. If the light keeps coming on and going off, look hard at the connector. For a quick read on your codes together, ask our AI mechanic.
What owners report to NHTSA
2 complaints filed with NHTSA mention P0447, 1 of them since 2015, across 2 different models. The component owners most often filed it under: electrical system.
Manufacturer service bulletins that name P0447
2 technical service bulletins and manufacturer communications filed with NHTSA mention P0447, from 1 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:
- JAGUAR XJ (2010, 2011, 2012, 2013), bulletin 10096676: "SITUATION: THE ENGINE MALFUNCTION INDICATOR LAMP (MIL) MAY BE ILLUMINATED. UPON DIAGNOSIS, THE TECHNICIAN MAY FIND ONE OR MORE OF THE FOLLOWING DIAGNOSTIC TROUBLE CODES (DTC) STORED IN THE ENGINE CONTROL MODULE (ECM): P…
Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.
Frequently asked questions
What is the difference between P0446 and P0447?
P0446 is the general vent control fault: the valve or its circuit isn't doing what the computer expects. P0447 is more specific: the circuit is open, so no current flows at all. That points you at wiring, the fuse or the valve coil rather than a blocked hose.
Can I drive with P0447?
Yes. The engine runs the same. You'll fail an OBD emissions inspection, and while the light is on for this, a new fault won't get your attention.
Can a gas cap cause P0447?
No. P0447 is an electrical code about the vent valve circuit. A bad cap sets leak codes like P0455 or P0456 instead. Leak codes can show up alongside P0447, though, because the computer can't seal the system for its test.
How much does it cost to fix P0447?
A fuse is under $20. A wiring or connector repair runs $100–$250 at an independent shop and a vent valve $120–$350. Where the valve is part of the canister assembly, expect $300–$800.