Chevy Impala P0446: EVAP Vent Control Circuit → Malfunction

The most frequent trouble code with the Chevy Impala The Code P0446. The trouble code refers to a number you receive when your Impala is plugged into an OBDII scanner. It indicates that an error has occurred in the evaporative emission controller system. You may see it along with the following codes: P0441, P0420 and P0440.

P0446: Evaporative Emission Control System → Vent Control Circuit → Malfunction

Normally, P0446 does not pose a threat to vehicle driveability. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. This is usually accompanied by P0442. A common problem code is P0420.

Chevy Impala P0446 OBDII Code Symptoms

Most commonly, the P0446 code does not cause any symptoms. Although the service engine light may come on soon, that's usually all. A slight drop in fuel economy is not uncommon. A slight gas smell may be caused by P0446. It is related to fuel vapors.

Chevy Impala P0446 Meaning

P0446 stands for a universal OBDII Trouble Code. The code is universal, meaning that it will be the same regardless of the make and model of your vehicle (Impala). Technically, the code stands for:

Evaporative Emission Control System Vent Control Circuit Malfunction

The EVAP captures any fuel vapor in the fuel tank, and transmits them to engines intake for ignition. If the EVAP control circuit vent control circuit does not respond to the ECU it will throw the OBDII code P0446 and the service engine light soon will illuminate.

Impala P0446 Trouble code Causes

You can trigger the P0446 code in Chevy Impala for many reasons. The most frequent problems that trigger this code are:

• Vapor Canister Purge Valve– One of the most common causes of the P0446 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.
• 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 code P0446. You should look for a hole or a tear in the fabric.
• The Faulty Charcoal Caister– The charcoal canister is often the cause of P0446.
• Fuel Tank Sending Unit– It is possible for the fuel tank sending unit to go bad. This could cause line pressure to drop and throw off the code.
• 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 P0446. This will save you time and money.
• 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.

P0446 Chevy Impala Diagnosis

To diagnose the problem with your Chevy Impala's P0446, a mechanic can use a variety of tools. The most commonly used methods to diagnose this code are:

• The mechanic will check to make sure there are no other 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.
• The mechanic will normally determine what trouble codes are associated with P0446. Take a look at the EVAP system. These include the line and purge valve.
• 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.
• Monitor and check the pressure in your fuel tank.
• Following the inspections and repairs, the mechanic will conduct two more tests.
• A smoke test, and they’ll use a scan tool to confirm that the EVAP solenoids and valves are operating properly.

The Most Popular P0446 Fixes

These are some of the most popular Impala P0446 solutions:

• Replacing the gas cap
• Replacing EVAP lines
• Replace charcoal canister
• Change the fuel tank

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 check your gas cap.

You will need to find the cause of your Chevy Impala throwing the code P0446. This should help. Feel free to add anything below. Enjoy your day.