How to Fix the Code P0446: What’s Behind the Issue

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evap vent control

Is your check engine light flashing? Dont worry, because error codes like P0446 has several ways to be resolved. But first, you have to know what the P0446 code is, the common symptoms, and the possible causes so you can address the problem correctly. Let’s get started!

What does Code P0446 mean?

The P0446 is an error code that indicates a problem with the Evaporative Emission Control (EVAP) system. This could usually mean a faulty vent valve, an inadequate control circuit for that valve, or a blockage in the vent valve itself. In all cases, it clearly shows the mechanic that a check of the EVAP vent valve is in order.

The vent valve is an important component in your EVAP system. Once the valve is activated, pressure will build up inside of the canister until no leaks or vacuum breaks happen during testing. So when the vent valve malfunction or damaged the code P0446 triggers.

Symptoms of P0446 Code

A issue with the (EVAP) Evaporation Control System can create a variety of symptoms that should not be ignored. If your OBD2 scanner displays a P0446 code, you may experience the following symptoms.

  • Check engine light or failure indication lamp illuminates
  • Noticeable fuel odor (relatively uncommon)

Causes of P0446 Code

The possible causes of the P0446 error code may vary depending on the make and model of your vehicle because different manufacturers offer different explanations. The following are the most common causes of an EVAP System Malfunction or code P0446:

  • A vent control valve that isn't working properly
  • Vent valve clogged
  • Difficulties with the control circuit (e.g., loose or damaged wiring)
  • Hardware or software difficulties with the powertrain control module (rather uncommon)
  • Damaged or cracked Fuel Tank Filler Neck
  • Damaged carbon canister
  • Shorted electrical connections

Although there are many possible causes; the most common cause of code P0446 is a problem with the vent valve. In some systems, vacuum pressure readings evaluate vent valve operation. As a result, unexpected elements can occasionally set off the code. Following are a few examples:

  • Failed charcoal canister
  • Faulty purge valve
  • Vent hose or vent filter clogged or pierced
  • EVAP system pressure sensor failure

How to Fix Code P0446?

As mentioned above, the error code P0466 has many causes, so there are no easy solutions. Also, remember that each car manufacturer has a different meaning for the trouble code.

If you are confident enough to fix the problem yourself, here's a step-by-step guide on how. But if you are hesitant to do so, please consult a licensed mechanic.

Tools You Need

  • OBD2 Scanner
  • Digital multimeter
  • EVAP smoke machine leak checker
  • Fused jumper wires
  • Vehicle specific service manual

Step-by-Step Guide

1. Check to see if P0446 is the only code on your vehicle. If there are any additional codes related to fuel pressure or the fuel system, fix and diagnose them first. It's most likely a solenoid failure, leaky charcoal canister, or a more complex EVAP leak if associated with P0441, P0440, and P0446.

Scan tool scanning the problem

2. Check to see if your gas cap is loose. If it's loosened, tighten the gas cap to possibly clear the code. If it was not loose, examine your gas cap for any signs of physical damage. Note that a damaged gas cap or deterioration of its components may not always be visible.

If your gas cap was not loose and there were no signs of failure, you should replace it regardless and clear the error code. Gas caps are inexpensive and frequently the solution to code P0446.

Car's gas cap

3. If the gas cap didn't work, examine the EVAP system for leaks: Remove the vent tube from the EVAP Vent Control Valve by pinching it. Use an EVAP smoke machine leak check to pressurize the EVAP system and check if any hoses or seals are leaking smoke. Check if any hoses or seals are leaking smoke. Repair any leaks and double-check that the problem has been rectified.

Checking the EVAP system for leaks

4. If there are no leaks, make sure the EVAP vent purge valve is working properly. This valve can become stuck, get clogged with debris, or the internal solenoid can fail and stop working. 

Remove the vehicle's EVAP purge control valve to put it to the test. Check that you can blow through the valve's apertures without power or ground. When power and ground are applied to the solenoid, the valve should click, and you should no longer be able to blow through the apertures. If you can blow through the valve when it's turned on, it's defective and should be replaced.

EVAP vent purge

5. Check again, and if the vehicle still sets the same code at this stage, you may have an electrical problem and need to take it to a mechanic for further diagnostic work.

Scan tool scanning a problem

Common Mistakes When Diagnosing the P0446 Code

As mentioned above, several things can cause P0446. Thus it's crucial to test them all to avoid a misdiagnosis thoroughly. Here are some mistakes when diagnosing P0446:

  • Jump too quickly to replace parts
  • Not checking other possible factors first
  • Not knowing where to look when checking for problems
  • Bringing the vehicle to the repair shop too soon
  • Assuming the problem is with the EVAP system when it could be a different system on the vehicle

P0446 Code FAQ

1. Is it safe for me to drive with the code P0446?

The P0446 code does not put you in any immediate danger. You can still drive your vehicle if this code appears. However, while this code is unlikely to be life-threatening, anything that illuminates the check engine light should be investigated right away.

2. Is the code P0446 serious?

Aside from the check engine light, the driver is unlikely to notice any P0446 symptoms. P0446 will not stop the car from running normally, but you should fix it as quickly as possible to ensure it runs properly

Driving with the check engine light up is not a good idea because an EVAP leak can be serious and environmentally damaging. Regardless of whether your car has proof of a fuel leak, you should have the codes removed as soon as possible.

3. How soon do I need to resolve the code P0446?

The sooner you have it repaired, the minor damage there will be to your vehicle. How quickly this code is resolved depends on the severity of the problem.

4. How much will I spend to fix the error code P0446?

The diagnostic trouble code (DTC) P0446 stands for "Evaporative Emission Control System Vent Control Circuit Malfunction." This can occur for various reasons, and a technician will need to determine what triggered the code in your circumstance.

One of our qualified mobile mechanics will visit your house or business and perform the Check Engine Light test for $114.99. After they've been able to diagnose the problem, you'll be given an upfront quote for the planned fix and a credit of $20.0 toward the repair. 

5. Is it possible to solve it on my own?

Yes, there are some things you can do to try and fix the problem on your own. However, depending on the cause, it might be best to take it to a mechanic for repair. Common DIY fixes for this code include replacing the vent control valve or cleaning out the EVAP system. How easy these repairs depend on your level of car expertise.


The P0446 code is not as serious as you think. However, keeping your car running smoothly by taking care of any minor issues can prevent major problems! You can resolve it in several ways, and this article has addressed some of them for you to consider.

An OBD2 scanner will help you diagnose and address the problem earlier. If you are unsure of how to use an OBD2 scanner, check the guide here to help you solve your problem.