P0449: Evaporative Emission System Vent Valve/Solenoid Circuit

Common causes

• A failed vent valve (vent solenoid) coil
• Broken or corroded wiring or connector, which is exposed to road spray and salt under the car
• A blown fuse or a problem in the valve's power supply
• On some vehicles the vent valve is built into the charcoal canister, so the canister assembly is replaced
• A fault in the engine computer's valve driver (less common)

Code meanings can vary slightly by manufacturer. Use these as a starting point and confirm with your vehicle's service information or a mechanic before replacing parts.

Symptoms

• Check engine light
• Usually no change in how the car drives
• Failed emissions inspection

Is it safe to drive?

Usually safe to drive with a steady light, but get it fixed to pass inspection.

How to check it with a scanner

1. Plug an OBD2 scanner into the port under the dashboard and read all stored codes and the freeze-frame data (the conditions when the code set).
2. With the engine off and the car safely supported on ramps or jack stands if you need to get underneath, find the vent valve near the canister and inspect the connector and wiring for corrosion or damage.
3. Check the fuse that feeds the EVAP vent valve.
4. Unplug the valve and measure its coil resistance with a multimeter; compare with your vehicle's spec.
5. If your scanner can command the vent valve, listen for it clicking.
6. After a repair, clear the code and drive normally for a few days to confirm it doesn't come back.

A basic code reader shows the code; scanners with live data let you watch sensor readings, which is what you need for most of the checks above. See OBD2 scanners under $100.

Questions

Related codes

• P0446: EVAP vent valve circuit
• P0455: Large evaporative (EVAP) system leak
• P0442: Small evaporative (EVAP) system leak
• P0443: EVAP purge valve circuit
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