P0449 Evap Emission System Vent Valve/solenoid Circuit

Code: P0449
Applies To: Most makes, generic code
Loose Cap Can Set It: Not named in our sources
Typical Fix: $182 at YourMechanic

A problem in the vent valve or its circuit.
A shop confirms it with the carmaker's EVAP test and a smoke machine before replacing parts.
Usually yes for now, but get it fixed soon and check for open recalls.

What The Carmakers Call It

EVAP emission system vent valve/solenoid circuit, as printed by Volkswagen Group of America
Evaporative Emission System, Vent Valve / Solenoid Circuit, as printed by Kia

Causes Named In Carmaker Bulletins

A blocked vent line, for example a spider nest, most often at the filler neck, when the valve and circuit test good (2017 and later Sportage) (source)
Water, dirt or corrosion at the canister vent valve (2007 to 2010 GM full size SUVs and Avalanche) (source)

No source ranks these by how often they happen, so they are listed as the bulletins give them.

No source ties P0449 to the gas cap.

What The Fix Costs

The usual part for this code is the vent valve. Published estimates put it at $182 at YourMechanic. The full table with every source and date is on the cost page. A diagnosis first keeps you from paying for a part you did not need, which is why we price what a check engine diagnostic costs before the fix.

Getting The Light To Go Off

After the repair the light goes off once the EVAP test runs and passes on three drive cycles in a row, and the code is erased after 40 warm up cycles, per CARB. The test only runs under set conditions such as a fuel level between about 15 and 85 percent, so it can take days.

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