What Are The Causes Of The P0449 Code?

Have you ever experienced issues related to the p0499 code in your vehicle? Its emergence indicates a lot about the condition of your car regarding the evaporative emission control (EVAP) system. Here, in the article, we will discuss all the essential points in contrast to the p0499 code. We will cover the contents like what it means, its signs and symptoms, causes, fixation, and certain frequently asked questions. So, let’s begin with the topic.

What Does The P0499 Code Mean?

Generally, the trouble code p0499 is mostly seen in the vehicles from the year 1996 to the present. However, it’s a generic code that is not universal. So, it is the evaporative emission control (EVAP) system that seals the fuel system of the vehicle to prevent fuel vapors from the fuel tank from escaping into the atmosphere.

When operating effectively, the EVAP system in the vehicle is responsible to capture the emissions and fumes produced while the fuel is processed. The design of the system varies according to the location and model of the engine. It emerges on the dashboard due to certain malfunctioning and defects in the vehicle.

What Are The Symptoms Of The P0499 Code?

The emergence of the p0499 code is pretty rare. However, it does not have any additional signs except for the emergence of the check engine light. Also, you can experience a certain level of fuel odor accompanying the code p0499. On the other hand, it majorly depends on the exact cause of your particular engine code.

There could be a variety of reasons for the emission of engine code in the vehicles which usually cause you to fail an emission test. However, some of the most common symptoms in the emergence of the code includes, check engine light, a failed emission test, no noticeable conditions, occasional fuel odor coming from the vehicle.

What Are the Causes Of The P0499 Code?

As we had discussed above, there are not many signs or symptoms determining and indicating the emergence of the p0499 code in the vehicles. However, there are tons of potential causes responsible for the creation or generation of such issues in the car.

Here, we will focus on some major causes, while some other causes include, damage to carbon canister, or damaged fuel tank.

1. Missing Fuel Cap

It is one of the most common causes responsible for the generation of issues related to the p0499 code. However, these problems are not as large as we expect, but they become pretty dangerous on ignoring and not correcting for the long term.

Dealing with such issues is extremely simple. If you are unable to reach the auto parts store for a new fuel cap then quickly stop up the fuel filler rag. It would help to prevent both gas and gasoline fumes from escaping your tank until you can buy a replacement.

2. Defective Evaporative Vent Valve

the failure or damage evaporative vent valve produces rough idling in the vehicle. As a result of all this, the vehicle will not operate smoothly. Hence, whenever you are driving it, it will function at an inconsistent rate or more particularly at low speeds.

Also, a damaged evaporative vent valve may lead to a vacuum leak causing an extreme level of rough idling.

3. Damaged Fuel tank Filler Neck

A bad or failing fuel tank filler neck may cause issues related to the emissions of the vehicle. And it can even become a safety hazard and more dangerous if the vehicle leaks any fuel.

The damaged fuel tank in turn produces certain symptoms while facing the situation, like fuel smell, fuel leaks, and the emergence of the check engine light. It can easily replace and the average cost may range around $220.

4. Defective EVAP Hoses

A defective EVAP particularly affects the engine’s overall performance. As a result, the engine faces less effective operation, it will produce a low power for high acceleration.

These certain issues may result in sluggish movement of the vehicle and it increases when you apply pressure on your gas pedal.

5. Defective Fuel Tank Sending Unit Gasket/Seal

The fault in such a system may cause the gauge to suddenly change the positions, or give an inaccurate reading. The gauge may seem to be at the three quarters and then within a few minutes later, it will change to a half-full, or particularly vice versa.

Some symptoms indicate that the fuel sending unit is bad and these include, fuel gauge reading empty when the tank is full, or fuel gauge is stuck on full. Also, fuel gauge fluctuation between empty and full is experienced in the vehicle.

How To Diagnose P0499 Code?

The diagnosing of the EVAP issues includes certain steps which need to follow sequentially to have an accurate and proper outcome. For this, first of all, use a professional scan tool to determine the codes stored in the electronic control unit (ECU). Next, analyze the freeze frame data associated with the codes.

Clear all the unnecessary codes, test run the vehicle to observe any signs that persist. Also, inspect the vent valve and wiring harness to look for any damage as majorly the damage will be found in these areas. However, if you do not find anything during a visual inspection, then use an advanced scan tool to test the EVAP functions.

How Do You Fix Trouble Code P0499?

Certain repairs would help you tackle the situation smoothly and properly whenever you are stuck in between such cases. It includes repairing or replacing the wiring harness, replacing the charcoal canister vent valve, repairing the damaged electrical connections, and replacing faulty ECU.


We hope the information mentioned above help and guides all the readers to deal with all the issues related to the p0499 code. We also, expect that by the end of the topic, you know a lot about the causes, fixation, and signs of the p0499 code.

If your doubts or queries related to the matter persist, please comment below in the comment section. And we will surely answer all your questions as quickly as possible.