Faulty or open-circuit EVAP vent valve solenoid; Damaged, chafed or broken wiring to the vent valve, often exposed to road dirt and water near the fuel tank or canister; Corroded, loose or water-damaged connector at the vent valve; Blown fuse or faulty relay supplying the vent valve, where fitted (depends on model); Open circuit or fault in the control unit output driver; Poor earth or supply connection in the shared circuit.

P0447

EVAP System Vent Control Circuit Open.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
47: FaultThe specific fault in that area

What it means

P0447 means the engine control unit has detected an open circuit in the evaporative emission (EVAP) system vent control circuit. The vent valve normally sits between the charcoal canister and fresh air, and is closed during leak tests. The control unit saw a voltage or current reading on the valve circuit that showed no continuity when it commanded the valve.

Symptoms

Engine warning light on
Difficulty refuelling, with the pump repeatedly clicking off
Smell of fuel vapour around the rear of the car
Failed emissions or readiness test with EVAP monitor not completing
No noticeable change in how the engine runs

Possible causes

Faulty or open-circuit EVAP vent valve solenoidlikely
Damaged, chafed or broken wiring to the vent valve, often exposed to road dirt and water near the fuel tank or canisterlikely
Corroded, loose or water-damaged connector at the vent valvelikely
Blown fuse or faulty relay supplying the vent valve, where fitted (depends on model)possible
Open circuit or fault in the control unit output driverrare
Poor earth or supply connection in the shared circuitpossible

How to diagnose

Read stored codes and freeze frame data, and note any other EVAP codes that may point to a shared cause.
Locate the vent valve for the specific model (usually near the charcoal canister or fuel tank) and visually inspect the valve, wiring and connector for damage, corrosion, water or dirt.
Check the relevant fuse and relay if the model uses them, following the wiring diagram for that vehicle.
Disconnect the connector and check the supply voltage and earth at the harness with a multimeter, following the manufacturer's procedure.
Measure the valve solenoid coil resistance and compare it with the specification for that model.
Check wiring continuity between the valve connector and the control unit, and test for short or open circuits.
Use a scan tool bi-directional test to command the vent valve and listen or feel for it clicking.
Clear the code and road test to confirm it does not return and the EVAP monitor completes.

How to fix

Replace the vent valve if the coil is open circuit or does not operate when commanded.
Repair or replace damaged wiring and use proper sealed connections.
Clean, repair or replace corroded or loose connectors and secure the harness away from heat and abrasion.
Replace a blown fuse or faulty relay after finding out why it failed.
Repair the earth or supply fault found on the circuit.
If all wiring and the valve test fine, diagnose the control unit driver per the manufacturer's procedure before replacing it.

Can I keep driving?

Low severity

The car can normally be driven as the fault affects only the EVAP system, but book it in soon. A stuck or unresponsive vent valve can cause fuel vapour smells or refuelling problems, and the car may fail an emissions test.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.