Chevy Sonic P0449 code Diagnosis: The EVAP Systems

This is a very common problem with the Chevy Sonic The Use code P0449. The trouble code refers to a number you receive when your Sonic is connected to a computer. OBDII scanner. The evaporative emission control system is P0449. This code is often found with or related to P0446 and P0420.

P0449: Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

Your Sonic's drive-ability is usually not affected by P0449. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. A scanner that is very accurate will allow you to identify if the valve works correctly. Most shops carry them. There’s a link towards the bottom the page on exactly how to perform that procedure. This article, however, is intended to help you diagnose the issue yourself.

Chevy Sonic P0449 Description

P0449 stands for a universal OBDII Trouble Code. The code can be used to indicate the same things regardless of the make and model of the vehicle (Sonic, or not) provided it was produced after 1996.

If P0449 is displayed, it means that either the solenoid circuit or the valve controlling the evaporation system are not working correctly. Depending on which vehicle model you have, the EVAP system converts fuel vapor from your gas tank to the intake manifold or charcoal canister. This system can fail to properly deal with fuel vapor if it malfunctions.

ECM (Engine Control Modul) detected a fault within the circuit controlling the vent to release fuel vapor. Soon, the service engine will follow this up.

Chevy Sonic P0449 OBDII Symptoms

The P0449 code is usually not accompanied with any other symptoms than those listed. Smells like gas And the service engine soon light. The slightest drop in fuel economy may also be noticeable.

The fuel tank or fuel filler tube should smell particularly strong.

The EVAP system is responsible for fuel vapors. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle.

Sonic P0449 Trouble code Causes

The P0449 code can be triggered by many factors in Chevy Sonic. These are some of the more common issues that can trigger the P0449 code. Here's a video explaining the process.

• Fuel Cap– A bad fuel cap can cause the code to be thrown for sure. Often, you’ll get a message informing you that the fuel cap is off even when it is on. It may be worth your time to get that message and a P0449 to ensure you don't waste any money.
• EVAP Hose– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. This can lead to the P0449 error code. It should have a hole or tear. This is the leading cause of code.
• Vapor Canister Purge Valve– One of the most common causes of the P0449 code is the vapor canister purge valve. It’s really easy to replace. There are some clips you will need to look for and then remove. Here’s How to check a purge device (YouTube).
• Trouble with Fuse/Wiring– If the wiring going to the valve has been compromise, it’ll lead to the P0449.
• Fuel Tank Sending Unit– It is possible for the gasket that attaches the fuel sending unit to the gas tank to go bad. It can lower the tank pressure, which could throw out the code.
• Fuel Filler Neck– There is often a gasket where the fuel filler neck connects with the gas tank. The gasket may dry out especially if the vehicle is in dry conditions. When it dries out, the fuel tank can’t hold pressure anymore, it may erroneously throw P0449.

Diagnostics for Chevy Sonic P0449

To diagnose the problem with your Chevy Sonic's P0449, a mechanic will have a variety of tools at his/her disposal. These are some of the common diagnostics that can be done for the code.

• To ensure that the cap can withstand pressure, the mechanic will check it. If you are getting a warning that your gas cap is off, even when it’s on, replacing it will more than likely clear this code.
• The mechanic will usually check for any additional trouble codes. It is easier to diagnose problems if there are more codes. That’s because when they appear together in certain combinations, there will often only be only a few conditions that will throw any combination of codes at one time.
• Once the mechanic has determined the trouble codes associated with P0449, he or she will usually Check out the EVAP System. These include the line and purge valve.
• Monitoring and checking the fuel tank pressure is a must.
• After for the checks and fixes listed above, the mechanic will perform two tests: A smoke test, and they’ll use a scan tool to confirm that the EVAP solenoids and valves are operating properly.

Have you got trouble with your computer? Here’s a Video with super technical content It is very detailed in diagnosing P0449.

Commonly Used P0449 Fixes

These are some of the most popular Sonic P0449 fix:

• Replacing the gas cap
• Replacement for EVAP Line
• Vent valve replacement
• Wiring repair

You should start with the gas caps and move on to the fuel tanks. This is because the gas caps are the easiest to replace and the least costly.

Here’s a great video on How to test your gas tank.

You will need to solve the problem quickly. This should help. You can add any additional information by leaving a comment.

Do you consider P0449 to be a serious concern?

While P0449 is not going to cause the Sonic’s engine to stop running, it should not be treated lightly. There could be fuel contamination. Check your tank regularly to make sure there is no fuel leaking. It is best to have it checked and/or dealt with immediately.