Chevy Suburban, P0449 Code Diagnostics: EVAP-System

This is a very common problem with the Chevy Suburban The Code P0449. The trouble code refers to a number you receive when your Suburban 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

Normally, P0449 does not pose a danger to Suburban driveability. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. You can also use a scanner to check if your valve is working correctly. They're common to find in most shops. There’s a link towards the bottom the page on exactly how to perform that procedure. This article will show you how to diagnose and fix the problem.

Chevy Suburban, P0449 Description

The universal OBDII code P0449 can be used to diagnose trouble codes. It means that no matter what make or model vehicle it is, P0449 will always mean the exact same thing. Suburbans and not.

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 module) has identified a problem in the circuit that controls the vent which releases fuel vapor. The service engine will soon follow up on this.

Chevy Suburban, 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. It is possible to notice a slight dip in fuel economy.

Particular attention should be paid to the smell of fuel near the fuel tank or fuel filler tube.

The EVAP process deals with fuel vapors directly. If these vapors are leaking from the system, you’ll often smell them faintly while operating the vehicle.

Problem Code Suburban P0449

P0449 can be triggered by many factors in Chevy Suburban. 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. You may not get the message but a P0449. This will save you time and 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. You should look for a hole or a tear in the code. This is the main problem that can cause the 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. It is possible for this gasket to dry, particularly if vehicles spend a lot of time in dry environments. When it dries out, the fuel tank can’t hold pressure anymore, it may erroneously throw P0449.

P0449 Diagnostics - Chevy Suburban

To diagnose the problem with your Chevy Suburban's P0449, a mechanic will have a variety of tools at his/her disposal. The most commonly used methods to diagnose this code are:

• A mechanic will examine the gas cap and verify that it is able to withstand high pressure. 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. A mechanic will usually check for additional trouble codes to help diagnose the problem. 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.
• The mechanic will normally determine what problem codes are associated with P0449. Take a look at the EVAP system. These include the line and purge valve.
• Monitor and check the pressure in your fuel tank.
• 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.

Are you still having problems? Here’s a Video with super technical content It is very detailed in diagnosing P0449.

Most common P0449 fixes

These are some of the most popular Suburban P0449 solutions:

• Replacement of gas cap
• Replacing EVAP lines
• Vent valve replacement
• Wiring repair

It is best to begin with the gas cap, and then work your way up to the fuel tanks. The gas cap is the most difficult and cost-effective item to replace.

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

You will need to solve the problem. This information is hoped to be helpful. Please feel free to add anything below.

Are P0449 Serious Concerns?

While P0449 is not going to cause the Suburban’s engine to stop running, it should not be treated lightly. Fuel leaks could be a problem. You should pay extra attention to the level of your fuel tank and ensure that you're not leaking fuel. It is best to have it checked and/or dealt with immediately.