What Does P0449 Code Mean On Your Car?

An EVAP leak is a fault in the evaporative emission control system (EVAP). The EVAP’s function is to keep gas fumes in the gasoline tank from reaching the atmosphere. This keeps air pollution down and keeps the smell of fuel from reaching the inside of your vehicle.

What Does Code P0449 Mean?

The evaporative emission control(EVAP) System seals the fuel system of the vehicle to prevent fuel vapors from the fuel tank. And fuel system from escaping into the atmosphere. This is important because fuel vapors contain a variety of hydrocarbons. Hydrocarbons from smog when they react with air and sunlight. Gasoline evaporates very quickly, so if the fuel system is open to the atmosphere, a vehicle can pollute 24 hours per day without even being turned on. When the trouble code P0449 code is set, this is an indication of the EVAP system vent valve solenoid malfunctioning which results in more hydrocarbons being expelled into the atmosphere.

What Are The Symptoms Of the P0449 Code?

Unfortunately, unlike other codes that have a variety of symptoms leading up to the trouble code, P0449 will probably only illuminate the malfunction indicator lamp. The lack of symptoms can be frustrating, especially with so many states requiring emissions testing for registration purposes. In case you are having a problem with this vent, it is possible that the MIL indicator might not light up immediately. You could fail the emissions test without an indicator beforehand. While unfortunate, the solution to this problem is perhaps affordable and nothing to worry about.

Common Signs Of A Problem With A Car?

Usually, a bad purge solenoid will display any of the following five symptoms that can alert the driver of a potential problem in need of service.

1. Rough Idle

One of the first symptoms that a faulty canister purge valve may produce is a rough idle. In this case, you will notice the car running inconsistently while stopped or driving at low speeds. If the canister purge valve fails and sticks open, it will create a vacuum leak that can affect the engine’s idle speed and quality. A vacuum leak can also be caused by a broken or damaged purge solenoid or any of the hoses attached to it. It needs to be addressed as soon as possible, as it could lead to your engine stalling completely.

2. Poor Engine Performance

On top of a rough idle, a vehicle with a failing EVAP canister purge valve will display signs of poor engine performance. The engine may feel like it’s running “weak” and won’t generate sufficient power for acceleration. Accelerating will feel like you are pressing the pedal down and moving slower. The disrupted combustion process caused by the failing purge solenoid will lead to slow acceleration that needs to be addressed for repairs right away.

3. Difficulty Starting The Car

Another symptom commonly associated with a bad vapor canister purge solenoid is difficulty starting the car. Again, if a vacuum leak is created as a result of any problem with the canister purge solenoid, that may cause the vehicle to have difficulty starting reliably. A vacuum leak will allow unmetered, outside air into the engine, which can disturb the air-fuel ratio. It also causes performance issues by interrupting the internal combustion process. Eventually, the engine may refuse to start entirely.

4. Check Engine Light Comes On

A defective canister purge solenoid may also set off the Check Engine Light. If the computer detects any problem with the purge solenoid circuit or signal, it will set off the light to alert the driver that a problem has occurred. A Check Engine Light can also be caused by a wide variety of other problems, so it is recommended to have the vehicle scanned for trouble codes to be sure.

5. Low Fuel Economy

Poor gas mileage is another sign of a failing canister purge valve. The fuel vapors your car usually uses for combustion will end up vented through the EVAP canister instead. Instead of reaching the combustion chamber, gasoline gets burned up before it engages in the combustion process. This means your car will not use fuel efficiently, and instead wastes gasoline.

The canister purge solenoid is an emissions component and is, therefore, an important piece in making sure that the vehicle meets emission requirements. The purge valve prevents toxic hydrocarbons in fuel from leaking out your tailpipe. For this reason, in case you suspect that your canister purge solenoid may be having a problem, have the vehicle diagnosed by a professional technician to determine. The canister purge solenoid or vacuum hose needs to be replaced for this case.

How Does A Mechanic Diagnose The P0449?

In case you face the problem of the P0449 code follows the below steps to diagnose.

  • Uses a scan tool to check for any codes stored in the ECU including history or pending codes.
  • Take note of the freeze frame data associated with the codes this is the conditions the vehicle was under when the malfunction set the Check Engine Light.
  • Clears all of the codes.
  • Takes the vehicle on a road test to confirm any symptoms that are present.
  • Performs a visual inspection of the wiring harness and the vent valve looking for any damage.
  • Uses an advanced scan tool to operate the EVAP functions. It enables the vent valve to function, checking for proper operation.
  • Checks for continuity between the vent wiring and ECU.
  • Perform a test on the ECU.

Cost Of Diagnosing The P0449 Code

P0449 is a diagnostic trouble code (DTC) for “Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction”. This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Mechanics to perform the check engine light diagnostic for 120$. Repair should be done once in a 12-month or every 12,000-mile.


While it is safe to drive with an EVAP leak, you should not drive your vehicle for long while you do leak. If your Check Engine Light comes on, check to make sure the gas cap on your vehicle is securely fastened. If the light is still on, take it to a mechanic so the leak can be fixed. It takes a professional to troubleshoot and repair a p0449 code leak.

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