Generic check engine light codes such as the P0446 will light up the check engine light out of nowhere. You likely won’t notice any symptoms at first, but you’ll know that something is wrong with the car.

In this article, you’ll find everything you need to know about the P0446 check engine light code. It points directly to the EVAP system, so we’ll cover what it means, the causes, common symptoms to look for, how to diagnose the issue properly, and how to fix it. You’ll also learn how serious this code is, and whether or not you can drive your car before getting it fixed.

What Is the P0446 Code, and What Does It Mean?

The P0446 fault code stands for Evaporative Emission Control (EVAP) system vent control circuit malfunction. Put in simpler terms, this code indicates that there’s a problem with the vent valve, the control circuit for that valve, or a blocked vent valve in the EVAP system.

What this means for the driver is that the car will most likely continue to operate normally, but it will fail the emissions test due to this issue. It also means that you’ll need to check the evaporative emission control system or other common causes.

What Causes a P0446 Fault Code?

There are a couple of common causes for the P0446 code. The most common is a damaged or missing gas cap. Other common causes include a faulty EVAP canister vent control valve, a damaged fuel tank filler neck, cracked or punctured EVAP hoses, a damaged carbon canister, a defective fuel tank, and bad electrical connections.

Gas Cap

What most people don’t realize is that the gas cap doesn’t only prevent fuel theft. It prevents harmful vapors from reaching the atmosphere, and it’s an important part of the EVAP system. If the gas cap is damaged, missing, or doesn’t seal properly, it can trigger the code P0446. Gas cap can also trigger the P0455 gross EVAP leak code, so make sure that it’s not on the OBD II error list as well. Because it’s the easiest part to reach, it’s recommended that you visually inspect the gas cap first. It’s also the most inexpensive part to replace and the most common cause for the P0446 fault code.

Vent Control Valve

A faulty vent control valve can also cause this code to come up. The job of the vent control valve is to move the fumes from the canister to the air intake manifold. If the vent control valve doesn’t work as it should, the fumes can either get trapped in the canister, or there won’t be enough pressure to keep the seal tight. Whether it’s stuck closed or open, a faulty vent control valve will cause the P0446 code.

Cracked Fuel Tank Filler Neck

The fuel tank filler neck is the last piece in the EVAP system before the gas cap. Although it’s not easy to damage it, it can still get cracked – thus allowing pressure to push out the fuel vapors. It’s not the most common cause for this issue, but it’s worth checking out either way.

Cracked EVAP Hoses

Cracked or punctured EVAP hoses are more likely to cause the P0446 fault code than a damaged fuel tank filler neck but are more difficult to reach. Due to constant temperature changes, vibrations, and pressure, these hoses can get damaged and cause issues to the EVAP system.

Charcoal Canister Damage

The carbon or charcoal canister as it is also known, is the main component of an EVAP system. If it gets damaged, it won’t be able to withstand the required pressure and cause the P0446 code to pop up.

Defective Fuel Tank

A defective fuel tank is also one of the possible causes for the P0446 fault code. Although it’s a difficult thing to crack a fuel tank, it’s still possible and if it’s cracked, it won’t be able to withstand the required pressure for the EVAP system to work properly.

Electrical Issues

Last but not least are electrical connections to the EVAP system. Wiring can get corroded and connections can get loose after some time. This usually won’t be the cause for the P0446 code in newer cars, but is a possible cause in older cars, especially those 10 years old or older.

Can a Purge Valve Cause P0446?

Yes, the purge valve can cause the P0446 code to come up if it’s faulty.

The purge valve is the last part between the EVAP system and the air intake manifold, and it opens up once there’s enough pressure in the EVAP system.

Because it’s sealed with an O-ring, it can sometimes leak vapors and cause this specific DTC to come up.

Where Is the EVAP Vent Valve Located?

In most cars, the EVAP vent valve is located somewhere on the outside of the car, most often underneath it. You’ll likely find it near the charcoal canister near the gas tank.

In some models, the vent valve is attached to the charcoal canister. You’ll notice two hoses attached to it. One side is attached directly to the canister or with a hose, while the other side is connected to a vent hose that’s attached to the vehicle body.

What are the Common Symptoms of P0446 Fault Code?

There are three possible symptoms that can point to the P0446 fault code:

• Check engine light
• Reduced fuel economy
• Smell of fuel around the car

The first and most noticeable is the check engine light. Although many issues can trigger the check engine light to come up, you’ll at least know that you need to use an OBD II scanner to read the codes that are stored in the car’s ECU.

The second symptom of the P0446 code is decreased fuel economy. This is a standard symptom for most codes related to the EVAP system, and it’s a clear sign that you should run diagnostics on your vehicle. Even changes in outside temperature can cause increased fuel consumption, so make sure to verify the symptom by running computer diagnostics on your vehicle.

The last of the common symptoms includes a strong smell of fuel near and inside the car. Because the EVAP system doesn’t seal properly, these fumes will be noticeable around the car. Exposing yourself to these fumes can be dangerous for your health, so if you can smell fuel around your car, make sure to check out the issue as soon as possible, especially if you leave the car in a garage that’s attached to your house.

How to Diagnose the Cause of P0446 Code

Diagnosing the cause of the P0446 code isn’t very difficult if you know where to look and have the required tools for the job. Using an OBD II scanner, read the codes stored in the ECU and make sure this is the only one before you start diagnosing the cause.

The first place to check is the gas cap. It’s the most common cause for the P0446 code, and it’s the easiest part to check. Visually inspecting the gas cap will give you a lot of information about its condition and whether it’s damaged and sealing correctly. If you notice any damage or wear to the gas cap, it’s likely what’s causing the check engine light and the P0446 code.

The next thing you should do is check the vent control valve. You can do this by simply removing the vent control valve from the vehicle and blowing in it. If you can’t blow through the control valve, it means it’s stuck closed, and it’s the part that’s causing the P0446 to come up. You’ll also need to test it while it has power. When the valve is connected to a power supply, it should be closed, and you shouldn’t be able to blow through the openings.

If the vent control valve is in good condition, you’ll need to do a smoke test and check for leaks in the EVAP system. Another common cause for the P0446 code is faulty wiring and connections, so make sure you check those out as well with a multimeter.

How to Fix P0446 Code

To fix the P0446 code, you’ll need to replace faulty parts within the EVAP system. We’ve covered how to find the cause, and here you’ll find information on how to fix the issue.

The gas cap is the most common issue to trigger the P0446 fault code, so we’ll start there. To fix the P0446, you’ll need to replace the faulty gas cap with an OEM one and reset the fault codes with your OBD II scanner. If this part was causing the issue, the code won’t come back, and you won’t see a check engine light on your dash. Also, the smell of fuel will disappear.

If the vent control valve is stuck or has debris in it that prevents optimal operation, the only way to fix it is by replacing it with a new one. Disconnecting the vent control valve and reconnecting a new one is a pretty straightforward process, but to reach it you’ll need to lift your car and use jack stands if you don’t have a professional lift.

To fix a leak in the EVAP system, you’ll need to replace faulty and worn-out parts. You’ll most likely need to replace one or more hoses, and as the vent control valve, it’s just a matter of removing the old parts and replacing them with new ones.

When it comes to electrical issues, you’ll need a multimeter, and you’ll probably need to check the service manual to make sure you’re using the correct wires. Replacing wiring or connectors requires using replacement parts with the same specifications, so the system will work properly.

After fixing the cause of the P0446 code, make sure you use your OBD II scanner and erase the code from the ECU.

Does P0446 Clear Itself?

This question can’t be answered with a simple yes or no answer. This mostly depends on the make and model of your car. Some cars will clear this code after you fix the cause, while other cars require the code to be cleared manually with an OBD II scanner tool.

Can You Drive with P0446 Code?

When it comes to the severity of the P0446 fault code, it’s not considered a very serious one when it comes to the car’s performance, and you can drive your car without fear that you’ll get stranded on the side of the road because of it. On the other hand, fuel vapors are considered a health hazard, and they should be addressed as soon as possible.

OEM Parts Provide Optimal Performance

Although the EVAP system doesn’t affect how the car drives and performs, it’s still an important part of any car. Regular maintenance and the use of genuine OEM parts will ensure you have a reliable car for years to come. That’s why we at eEuroparts.com are very selective when it comes to the parts we offer.

Only genuine, OEM, and high-quality aftermarket parts can be found on our website, and by picking the make and model of your car in the car picker tool, you won’t have to worry about part compatibility. We guarantee a proper fit!