P0449: All You Need To Know To Fix Your EVAP System

by Conner Mckay

The P0449 is classified or is a part of the Diagnostic Trouble Codes (DTC). These codes are five-digit numbers that point out or identify a part of the car that may be malfunctioning or having problems. These codes can usually be displayed on any OBD scanner when it is connected to the car’s system.

This five-digit code usually includes one letter at the start followed by four numbers (e.g. P0449). Each combination on the code relates to a specific problem faced by the car. It can be a generic issue, a manufacturer-specific issue, or the malfunctioning of a certain part.

A Diagnostic Trouble Code will not specify the part of the car that needs to be fixed or replaced. It rather notifies you of the things that need to be tested to diagnose and get rid of this issue.

P0449 Evaporative Emission Control System Vent Valve/solenoid Circuit Malfunction

The error code P0449 comes under the generic powertrain code. This error code can be found in all the makes and models of vehicles that were manufactured after 1996. Like every other DTC, the P0449 indicates a problem within the Evaporative System Vent Control Circuit.

The evaporative system vent control circuit is designed in such a way that it captures and gets rid of any fuel vapors in the storage system. It does not allow these toxic pollutants to leak into the atmosphere. The EVAP system stores these vapors in a charcoal canister, until they can be reintroduced in the combustion cycle.


When the ECU detects a problem with the evaporative emission system vent control circuit, the code P0449 is shown on the reader.

P0449 Code Symptoms

The error code P0449 is one of the rarest engine codes that does not have any additional symptoms instead of the check engine light. When your vehicle is facing this problem, occasionally there will a fuel odor that comes with this problem. The fuel smell problem usually depends on a certain part of the EVAP.

Usually, when a vehicle is facing the error code P0449, the only noticeable symptom is the check engine light. However, any car facing this emissions-related engine error code will usually fail an emissions test. Here is a list of the minor symptoms that can be seen faced with this problem.

What Causes A P0449 Code

The list of causes is huge when compared to the small list of symptoms for the error code P0449. One of the most common causes of the error code P0449 is a missing or damaged fuel cap. However, if your luck is not in your favor, you will have to inspect the rest of the vehicle for damages relating to this problem.

Different parts like defective vent valves, fuel tank filler necks, EVAP hoses, carbon canisters, and fuel tanks are all the obvious parts to look at when your car is showing this particular error code. Since the P0449 error code relates to there being a leak in the evaporation system, that is why anywhere that fumes could be escaping can be a potential cause.

  • Missing or damaged fuel cap
  • A broken evaporative vent valve
  • Damaged or broken fuel tank filler neck.
  • Broken EVAP hoses.
  • Defective fuel tank seal.
  • Broken carbon canister.
  • A leak in the fuel tank.

How Serious Is This?

Several people who are reading this article will be wondering about how serious this code and problem are. Well, any and every car owner out there should address any check engine light that comes up. This is extremely important for maintaining and properly taking care of the vehicle you own.

To answer the question on everyone’s mind, an error code  P0449 is one of the least serious reasons for a check engine light a car can have. It is extremely affordable to repair and it usually does not have any negative effect on your car. Hence, you can put off repairs for a while. However, it is advised to pinpoint the exact cause of the problem before putting off any repairs to be on the safer side.

Every person facing this problem needs to keep in mind that having a check engine light on will further prevent your vehicle from notifying about any new problem that might emerge. In conclusion, while the error code P0449 might not be the be serious or create any further problems for your car. However, if a new code pops up that is serious, you might not know about the problem unless and until it is too late. This can be problematic for your car and your finances as well.

P0449 Chevy Silverado

There are several different error codes that can help a mechanic to identify different problems on your Chevy Silverado. The P0449 is one of the error codes that can be identified on your chevy. Usually when this error code is detected in the Silverado, then you need to understand that there is a problem with the Evaporative Emissions Control System (EVAP).

The question that several Chevy Silverado owners have is the seriousness of this error code and how expensive is it to fix this code. Another question might be how do the owners identify this problem? Do not worry we have you covered.

Symptoms Of Getting The Code P0449 On A Chevy Silverado

Like every other problem out there, the error code P0449 also has certain symptoms to identify this problem. Here is a list of all the symptoms that would help you find out if your Chevy Silverado is facing this problem. Here is a list of symptoms that will help you-

  • The check engine light is turned on.
  • The smell of fuel being evaporated is noticeable.
  • An OBD reader will show error codes P0449, PO441 code, P0440, and P0446.
  • There have been cases in which the engine cranking is also delayed.

Luckily there are no issues regarding the drivability of this car. If you are facing any of these problems with your Chevy Silverado, you need to take proper precautions to fix or get over this problem.

Causes Of the Error Code P0449 Chevy Silverado

There are several factors that might be causing the error code P0449 on your Chevy Silverado. Here is a list of all the common reasons why your Silverado might be experiencing this problem.

  • Problem With The Vent Wiring – Usually when the wiring of the vent valve of your Chevy Silverado becomes loose or breaks, the error code P0449 is shown.
  • Faulty Fuel Cap – A faulty fuel cap might be the reason for your Silverado to face the problem P0449. A faulty fuel cap means you will get a signal of a fuel cap being off even though it is on. If you receive this signal, your car is facing the error code P0449 Chevy Silverado.
  • Bad Vapor Canister Refining Valve – This problem is one of the most common reasons for your Silverado facing the error code P0449. This problem will cause the truck’s check engine light to light up. Alongside that, the Silverado will have poor performance and engine problems.
  • Problematic Fuel Tank Sending Unit – The gasket is what supplies the fuel to the gas tank. A gasket is what connects the fuel sending unit to the gas tank. If there is any problem in the unit, the error code P0449 arises.
  • Fuel Filler Neck – A gasket is what connects the fuel filler neck and the gas tank. The gasket of the vehicle dries up sometimes due to relatively dry weather. Due to this dryness, pressure is created in the gas tank and the code P0449 is detected.

How Serious Is The Error Code P0449 Chevy Silverado

The code P0449 is not responsible for any serious damage to your truck. The P0449 is an emission control code. The main problem is that the evaporative duel in the truck is disrupted and you get a slight odor. Your Silverado will not face any performance problems but it is advised and wise to get rid of the problem as soon as possible.

P0449 Chevy Impala

The error code P0449 is an extremely common problem faced by the Chevy Impala. The error code P0449 normally does not impact the driveability of your Chevy Impala as said before. The P0449 is a universal OBD2 trouble code that indicates that there is a problem with the evaporation system. This means like every other vehicle which was manufactured after 1996, your Chevy Impala will also show this code while facing this problem.

The EVAP system’s responsibility is to cycle the fuel vapors from the gas tank into the charcoal canister, intake manifold, or directly into the air. If the EVAP malfunctions, this vapor is not being dealt with.

P0449 Chevy Impala Symptoms

The P0449 error code on the Chevy Impala is not something that you should worry about. This code usually does not come with any noticeable symptoms. The only symptoms reported by Impala owners were the smell of gas and the service engine soon warning popped up on the dash. Another one of the more prominent problems was that Chevy Impala owners noticed a slight dip in the fuel economy as well.

The smell of the fuel is particularly noticeable around the fuel tank area or the fuel filler tube. The EVAP system is responsible for taking care of the fuel vapors. So when you are facing this problem, you can smell these vapors faintly while driving your Chevy Impala.

Causes Of the Error Code P0449 Chevy Impala

There are a number of reasons that can cause the error code P0449 to pop up on your Chevy Impala. You need to look closely at these causes or reasons to get over this problem as there are barely any symptoms but several reasons. Here is a list of things you need to look out for on your Chevy Impala if you are facing the P0449 problem.

Fuel Cap

 A bad or malfunctioning fuel cap can be the cause for your Impala to show the code P0449. This happens when you get a warning “fuel cap is off” even when it is on. You can change the fuel cap to see whether or not your car is still showing the P0449 error code.

EVAP System Hose

To put this in simpler terms, this happens when the hose that carries the fuel vapor from the fuel tank to the intake manifold starts to leak. This is usually what generates the code P0449. You need to look whether for a tear or a hole in the pipe. This is one of the most common issues that cause this problem.

Vapor Canister Purge Valve

Another one of the most common issues that cause the P0449 code is the vapor canister purge valve malfunctioning. It is very easy to replace and can be done with the help of DIY videos.

Fuse/Wiring Problems

If the wiring that controls any of the steps in the EVAP has been broken or malfunctioning, it will be left to the P0449 error code.

Fuel Tank Sending Unit

The gasket that attaches the fuel sending unit to the gas tank has a possibility of going bad. This can reduce the pressure in the tank causing the Impala to show the code P0449.

Fuel Filler Neck

The gasket that connects the fuel filler neck and the gas tank can dry out. This usually happens when your Chevy Impala has spent a significant amount of time in dry climates. When this dries out, the fuel tank can’t hold a lot of pressure causing the Chevy to show the code P0449.

How To Fix Code P0449

Having the error code P0449 might not be one of the most serious error codes out there. This error code does not affect the health of the car or the drivability. The P0449 code notifies us about a malfunction in the EVAP system. This may have very limited symptoms but several causes so here is all you need to know to fix the P0449 error code.

Fixing Or Replacing Fuel Cap

By far one of the most common problems that can cause an error code P0449 is a damaged fuel cap. It is extremely easy to replace and fix. Alongside that, it is also very economical on the pocket. A damaged fuel cap will indicate that the fuel cap is off even when that is not the case.


Installing a new gas cap is an extremely easy process. There are several types of gas caps in the market like pressure release gas caps, metal push on gas caps, or standard gas caps. Here is a link that will help you know everything about fixing and replacing the gas cap.

Fixing Or Replacing EVAP leaks

Out of all the different reasons for the code P0449, the EVAP leaks can be the most irritating and difficult to locate and fix (as is the case with the BMW P0442 problem). A leak in the EVAP system can be the cause of the P0449 error code. Common leak locations include the charcoal canister, hoses and seals, and EVAP canister vent valves. Or, the EVAP canister vent solenoid.

Charcoal Canister

A puncture or a hole on the charcoal canister is the most common and is the most probable reason for the canister. The charcoal canister is placed under the car and near the tank. The puncture or the hole in the canister can be caused due to rough driving conditions. To get the charcoal canister, you need to show your car to a mechanic. They can be extremely tricky to get to and so it is better to let a specialist take care of the problem.

Seals And Hoses

Another common reason for a leak in the EVAP system is the seals and hoses that connect the different parts of the system. Defective or damaged O-ring seals or hoses have a tendency of drying up which can further cause a leak in the EVAP system. Unfortunately, there are several of these seals and hoses which need to be checked. What you need to do is check all of these hoses individually until you find the leak.

Canister Vent Valve

A hole or a leak in the canister vent valve is another thing that is common with the P0449 code. The canister vent valve is responsible for carrying the vapors produced while driving into the charcoal canister. If you drive an old car, it is possible that the valves don’t close properly and some of the fumes get released into the environment.

The canister vent valve is placed right beside the charcoal canister. This means that rough driving conditions can be the culprit that might cause the vent to malfunction. Replacing the canister vent should help you get over the problem. You need to take your car to the mechanic to get the canister vent valve changed. This will further help you to get over the problem P0449.

Repairing Faulty Electronic Connections

Faulty or broken electronic conditions can be the root cause of the error code P0449. Broken or faulty wiring can cause the EVAP to not work properly which might cause a leak in the fuel vapors. In order to get over this problem an individual needs to check all the wiring, especially the ones that connect to the EVAP.

You need to make sure that the EVAP is getting an adequate amount of energy in order to work properly. You can also show your vehicle to a mechanic as they are more equipped to face a problem like this. He can also pinpoint the problem faster and without a problem.


If you have checked all of these possible problems above, there are other possible issues that may be causing the error code P0449. This is when you need to consult a specialist or a mechanic to get over the error code P0449.

How Much Does It Cost To Fix The Code P0449

The cost of getting rid of the error code P0449 is not very high. The majority of the bill will consider the labor fee which depends upon the time put into fixing the car. This labor fee usually depends upon the type of shop you end up taking your car to. Usually, an hour of labor fee can cost anywhere between $75  and $150.

When you take your car for diagnostics, most shops will start with an hour of diagnosis time. Many if not all of the shops add this “diagnosis time” in the final bill. Once they have diagnosed the problem only further can they give you an estimate of how much will it cost to get rid of the error code P0449?

Figuring out the problem to fix the error code P0449 can be extremely tricky. One or more parts can be the reason behind the car having this problem. The total bill will vary from the amount of money spent on parts and the time taken to change those parts and get rid of the problem.

For each possible repair, here is the estimated cost of repairing or completely changing the part. It may vary depending upon the car as well as the place where you get it fixed.

  • A Gas Cap will cost anywhere between $20-$60
  • A new EVAP Line costs about $20-$100 to repair
  • The EVAP Vent Control Valve can cost you around $150-$200
  • Lastly, the Purge Volume Control Valve will be about $150-$200

Facts about P0449 Error Code in a Vehicle’s EVAP System:

  1. P0449 indicates a malfunction in the vehicle’s evaporative emissions control (EVAP) system’s circuit that controls the vent.
  2. P0449 is a variation of a vehicle’s on-board diagnostic system’s (OBD II) code P0.
  3. All P0 codes are generic, and they could apply to any make and model.
  4. The most common indication/symptom of a P0449 error code is the illumination of the vehicle’s check engine light.
  5. A fuel-like odor in the cabin of the vehicle or around the vehicle itself is another symptom of P0449.
  6. The vent valve in an EVAP system is designed to open at times when there are minimal conditions creating fuel vapor or hydrocarbons.
  7. Dysfunction of the vent valve in the EVAP system is the most likely cause of P0449.
  8. Releasing toxic and flammable vapors in the cabin can be very dangerous for the driver and their passengers.
  9. Seeking the expertise of a professional mechanic is the best way to diagnose and repair P0449.
  10. Repairing P0449 can be as simple as securing or replacing a damaged or faulty gas cap.


As said at the start of this article the error code P0449 is a generic powertrain code. Like every other DTC, the P0449 indicates a problem within the Evaporative System Vent Control Circuit. The symptoms of the error code P0449 might be extremely limited but the causes for this problem are high.

This might not be one of the most serious error codes out there, but it is advised to get rid of the code as soon as possible. P0449 might not cause any problem with the drivability of your car.  However, if a new code pops up that is serious, you might not know about the problem unless and until it is too late.

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