Nissan Patrol P0446: EVAP Vent Control Circuit → Malfunction

This is one of the most commonly encountered trouble codes for the Nissan Patrol The P0446 Code. The trouble code refers to a number you receive when your Patrol 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

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. P0442 is commonly accompanied. Another common code for trouble is P0420. It often comes with P0446.

Nissan Patrol 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 vapor system.

Nissan Patrol 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 the vehicle. Technically, the code stands for:

Evaporative Emission Control System Vent Control Circuit Malfunction

The EVAP system collects fuel vapor from fuel tanks and then sends it to the intake of the engine to ignite the normal combustion process. The EVAP control control circuit will not respond to an ECU if it detects a problem with the vent control circuit. This will cause the engine's service light to illuminate and throw the OBDII P0446 code.

Patrol P0446 Trouble code Causes

You can trigger the P0446 trouble code in your Nissan Patrol by a variety of reasons. These are some of the more common reasons that the code will be triggered:

• 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. This can lead to the code P0446. It should have a tear or a hole.
• 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.
• 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. 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 Patrol

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

• A mechanic will usually check for any additional trouble 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.
• The mechanic will then perform the following tests after completing the above-mentioned checks:
• A smoke test, and they’ll use a scan tool to confirm that the EVAP solenoids and valves are operating properly.

Most common P0446 fixes

Below are the top Patrol P0446 solutions:

• Replacement of gas cap
• Replacement for EVAP Line
• Replace charcoal canister
• Replacing 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.

We wish you all the best in finding out why your Nissan Patrol is throwing the P0446 error code. We trust this helped. Feel free to add anything below. You have a wonderful day.