Nissan Titan P0446: EVAP Vent Control Circuit → Malfunction

This is one of the most commonly encountered trouble codes for the Nissan Titan The Code P0446. This trouble code is a reference to a number given when you connect your Titan to an OBDII scan. The code P0446 indicates that the evaporative emissions control system is failing. This code is often found with P0441 or 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. It's often associated with P0442. Another common code for trouble is P0420. It often comes with P0446.

Nissan Titan 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. You may notice a gas smell after using P0446. Because it is connected to the fuel vapor system, P0446 may also cause a slight gas smell.

Nissan Titan P0446 Meaning

P0446 stands for a universal OBDII Trouble Code. It means that no matter what make or model vehicle you have, this code can mean the exact same thing. Technically speaking, it stands for:

Evaporative Emission Control System Vent Control Circuit Malfunction

The EVAP captures any fuel vapor in the fuel tank, and transmits it 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.

Titan P0446 Trouble code Causes

P0446 can trigger the code in your Nissan Titan. 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. The P0446 code will be generated. 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. It may be worth your time to get that message and a P0446 to check if the fuel cap is working.
• Fuel Filler Neck– There is often a gasket where the fuel filler neck connects with the gas tank. It is possible for this gasket to dry, particularly if vehicles spend a lot of time in dry environments. When it dries out, the fuel tank can’t hold pressure anymore.

P0446 Diagnosis- Nissan Titan

The mechanic will have a lot of different tools at his disposal in order to determine the cause of your Nissan Titan 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. It includes the purge valve and line as well as the canister.
• 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.
• Monitoring and checking the fuel tank pressure is a must.
• 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

Below are the top Titan P0446 fix options:

• Replacement of gas cap
• Replacing 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 the gas cap.

We wish you all the best in finding out why your Nissan Titan is throwing the P0446 code. This should help. Please leave us a comment below if you have any suggestions. You have a wonderful day.