P0442 Code – Meaning, Causes, Symptoms (& How To Fix)

The P0442 is a widespread trouble code due to its nature of appearing. Find out the meaning, symptoms, causes, and how to fix the P0442 code.

P0442 Code

There’s never a good time to have the Check Engine Light come on. However, some codes aren’t as serious as others, making them more manageable to deal with. One such DTC is the P0442 code.

While it can be alarming before you know about it, there’s not normally a major problem to deal with. That doesn’t mean it should ever be ignored. 

Continue reading to find out what the P0442 trouble code means and what symptoms it causes. We also review the most common symptoms and show you how to fix it. 

Code P0442 Definition

P0442 – Evaporative Emission Control System Leak Detected (Small Leak)

What Does the P0442 Code Mean?

The P0442 trouble code shows a minor leak in the EVAP system. While it’s referred to as a leak, what it really means is that the EVAP system isn’t holding the proper amount of vacuum for a particular amount of time. If these parameters aren’t met, the code sets.

The evaporative emission control (EVAP) system keeps fuel vapors from escaping into the environment. Fuel vapors from the tank get absorbed by the charcoal that is in the canister. There’s also a vent control valve that is run by the ECM, allowing air to flow into the canister, so the gas vapors can be purged. We encourage you to look at a diagram of your car’s EVAP system, as they can all be set up differently. 

What Are The Symptoms Of P0442?

The great thing about the P0442 DTC is that it doesn’t normally include any unusual symptoms. Aside from seeing the Check Engine Light, you might not have known that something was wrong. 

However, it’s possible to deal with these problems with this code.

  • Check Engine Light
  • Faint smell of fuel
  • Failed emissions test

What Are The Causes of P0442?

Because the P0442 deals with the evaporative emission control system, any part of this can malfunction and lead to the trouble code. However, it could also be something as small as a loose fuel cap. For this reason, an in-depth diagnosis is needed.

Here are the most common causes leading to the P0442 code.

How Serious is the P0442 Code?

Low – The P0442 trouble code isn’t usually going to create any driveability issues or lead to any other damage. For this reason, it may be okay to wait a short time to have it fixed.

Still, while the EVAP system isn’t working as it should, more emissions are entering the atmosphere than they should. For this reason, it’s important to have it fixed as soon as you are able. Not only that, but the car could fail an emissions test. 

On the other hand, if you have a damaged fuel tank, this would be a problem you wouldn’t want to wait on. While it’s not normally the case, leaking fuel could cause many more issues, even to the extent of creating a car fire. 

Car Leaking Gas Cap

How Do I Fix the P0442 Code?

The only proper way to fix the P0442 trouble code is to start with the right diagnosis. We advise you to follow the steps outlined below to determine what fix is needed.

You may find that one of these potential fixes resolves the issue.

  • Tighten or replace the fuel cap
  • Repair damaged EVAP system line
  • Replace EVAP purge control valve
  • Replace charcoal canister
  • Repair damaged fuel tank
  • Replace vent valve
  • Replace FTP sensor
  • Replace leak detection pump

Common P0442 Diagnosis Mistakes

Most people want to jump right into diagnosing the EVAP system. They prepare to do leak tests and expect the worst. In the process, they overlook the easiest solutions.

For many people, it only takes tightening up the gas cap to remove the code. If you are jumping right to complicated issues, you could end up spending money and time that’s not needed. Begin with the simple tasks first. 

It’s also possible that you didn’t turn off the car while refueling, which will cause the P0442 code and you need to use an OBD scanner to clear the code.

Evap Purge Control Valve
EVAP Purge control valve, a common cause of the P0442 code

How to Diagnose the P0442 Trouble Code?

If you want to figure out the P0442 code as mechanics do, you need to follow a certain protocol. Gather your code scanner and follow through with these steps.

  1. Check engine codes with an OBD scanner. If there is more than a P0442 code, you might get more information regarding the problem. For example, the P0440, P0441 or P0446 codes may indicate a complex EVAP leak, a bad charcoal canister or solenoid failure. 
  2. Inspect the gas cap. If it’s loose, tighten it up and see if that resolves the problem. If you notice any damage to the gas cap, you need to replace it. Some people prefer to replace it even if the damage isn’t noticeable because it’s such a cheap fix and there could be problems you don’t see. 
  3. Inspect the EVAP hoses going to the air box. If you notice any hoses that are disconnected, cracked or damaged, take care of them. 
  4. Inspect the fuel tank for any damage. Repair any problems.
  5. Inspect the charcoal canister for damage and replace it if needed.
  6. Examine the purge volume control valve. When there’s no power source, the valve won’t be powered on and air doesn’t pass through. However, it can stick, which would lead to leaks. Replace it if there’s a problem.
  7. Check the vent control. This charcoal canister vent is also not on when there’s no power source. It’s another valve that can get stuck, leading to leaks. 
  8. Perform a smoke test with an EVAP smoke machine to look for leaks. 
  9. Read service bulletins from the manufacturer if you are stuck. 

Not everyone is equipped to deal with this trouble code. If the diagnosis is getting beyond your expertise or you can’t handle the repair on your own, it’s always best to reach out to a professional mechanic for more support. 

How Much Does It Cost To Fix Code P0442?

We have some repair estimates on the top fixes for the P0442 code. These prices include labor and parts, so you may be able to reduce the cost if you perform the work on your own. 

  • Tighten or replace fuel cap – $0-$50
  • Repair damaged EVAP system line – $75-$600
  • Replace charcoal canister – $150-$600
  • Repair damaged fuel tank – $750-$1,500
  • Replace vent valve – $100-$350
  • Replace purge control valve – $100-$350
  • Replace FTP sensor – $250-$500
  • Replace leak detection pump – $150-$450

A Mechanic’s Tips About The P0442 Code

Not all vehicles have the P0442 trouble code in their library. In fact, the majority of modern Toyota models don’t have the P0442 code.

Aside from that, not all EVAP systems are set up the same way. For that reason, it’s essential to read through your service manual before trying to do a leak test or any other diagnostics. 

Frequently Asked Questions

Is it OK to drive with a P0442 code?

Yes, you aren’t going to create any other damage or have driveability problems with the P0442 code in most cases. Still, emissions are leaking into the environment that shouldn’t, so you don’t want to procrastinate for too long. Do your part and get the problem fixed as soon as you can. 

How serious is a small EVAP leak?

When it comes to how the car runs, it usually isn’t a big deal. You may not even notice that there’s a problem. With this fault, emissions are leaking into the environment at higher rates than they should, so you don’t want to completely ignore it. Plus, you won’t be able to get the Check Engine Light off until it is repaired. 

How long does it take to clear P0442?

If the problem is a leaky gas cap, you can fix the issue within a few minutes. Some of the more advanced problems could take additional time to fix. The only way to know for sure is to work through the complete diagnostic procedure to determine what’s wrong. 

Can a bad gas cap cause a P0442 code?

Yes, if the gas cap is cracked or damaged, the emissions system will leak. It shouldn’t cost much more than $10 to get a new gas cap. This simple fix ensures that emissions don’t leak into the environment and it makes it possible to reset the Check Engine Light for a worry-free drive. 

Conclusion: P0442

While many trouble codes provide a reason for real concern, the P0442 DTC isn’t normally one of them. In most cases, the problem is simple enough to fix and there won’t be any drivability issues. Still, you should never overlook anything causing the Check Engine Light to come on.

Make time to perform diagnostics as soon as possible and repair the fault to turn off the light. Not only will you feel better about the well-being of your car, but you know you are doing your part for the earth. Plus, you won’t have to worry about failing your next emissions test either. 

Magnus Sellén
Written by:

Magnus is the owner and main author of Mechanicbase. He has been working as a car mechanic for over 10 years, and the majority of them specialized in advanced car diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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