Toyota Tacoma P0446: EVAP Vent Control Circuit - Malfunction

Common trouble codes for the Toyota Tacoma The P0446 Code. The trouble code refers to a number you receive when your Tacoma 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: P0440, P0441 and P0440.

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

The P0446 problem is not usually a serious threat to your car's 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. Another common code for trouble is P0420. It often comes with P0446.

Toyota Tacoma P0446 OBDII Code Symptoms

Most commonly, the P0446 code does not cause any symptoms. You will see the light on your service engine shortly, but this is typically it. It is possible to notice an increase in fuel consumption, but it is unlikely. A slight gas smell may be caused by P0446. It is related to fuel vapors.

Toyota Tacoma P0446 Meaning

The universal OBDII code P0446 can be used to diagnose trouble codes. The code can be used regardless of the make and model of your vehicle. 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.

Tacoma P0446 Trouble Code Causes

P0446 can trigger your Toyota Tacoma's trouble code. These are some of the more common issues that can trigger the P0446 code.

• 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. You will need to locate and take out a few clips.
• EVAP System Hose– The hose that carries the fuel vapor from the fuel tank to the intake manifold can begin to leak. The P0446 code will be generated. You should look for a hole or a tear in the fabric.
• A Faulty Canister of Charcoal– 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. It can cause a disruption in the line pressure, throwing off the code.
• Capacity for Fuel– 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 Diagnose- Toyota Tacoma

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Toyota Tacoma P0446. These are some of the common diagnostics that can be done for the code

• The mechanic will check to make sure there are no other 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 trouble codes are associated with P0446. Check out 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 common P0446 fixes

Below are the top Tacoma P0446 fix requests:

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

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 check your gas cap.

You will need to solve the problem quickly. We trust this helped. Please leave us a comment below if you have any suggestions. Enjoy your day.