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P0442 OBD-II Evaporative Emission System Leak Detected (small leak) Trouble Code




The P0442 code is an OBD-II trouble code that stands for “Evaporative Emission Control System Leak Detected (Small Leak)” which indicates that the Evaporative Emission Control (EVAP) System is leaking.

In this article, I will be talking about the P0442 trouble code, its symptoms, causes, and how to fix it.

What Does The P0442 Code Mean?

P0442 OBD-II Evaporative Emission System Leak Detected (small leak) Trouble Code

The P0442 trouble code means a small leak in the EVAP system. While it’s referred to as a leak, it indicates that the EVAP system isn’t holding the required quantity of vacuum for a specified period. If these conditions are not met, the code will be set.

The evaporative emission control (EVAP) system prevents the release of fuel vapors into the atmosphere. The charcoal in the canister absorbs fuel vapors emitted from the tank.

The engine control module (ECM) also controls a vent control valve that allows air to flow into the canister so that gas vapors can be expelled. We recommend that you examine a diagram of your vehicle’s EVAP system, as their configurations vary.

(Related: P0456 OBD-II Evaporative Emissions System Small Leak Detected Trouble Code)

Which Models Are Affected By The P0442 Code

MakeAffected By P0442 Code

What Are The Possible Causes of the P0442 Code?

The P0442 trouble code can be triggered by a variety of Evaporative Emissions Control system-related causes.

Here are the possible causes of the P0442 trouble code:

  • The fuel cap is damaged or loose.
  • Faulty evaporative emission control (EVAP) system line.
  • Defective purge volume control valve.
  • Defective canister vent control valve.
  • The fuel tank is leaking.
  • Faulty fuel tank pressure (FTP) sensor.
  • Faulty pump for leak detection.

(See also: Can a Charcoal EVAP Canister Be Cleaned? (Answered!)

What Are The Common Symptoms of The P0442 Code?

Typically, the P0442 trouble code does not appear with obvious symptoms. Nonetheless, there are a few typical EVAP code symptoms that you should be aware of.

Here are the most common symptoms of the P0442 trouble code:

  • The check engine light: It is nearly impossible to detect an EVAP leak physically. Therefore when the exhaust system’s leak-detecting pump suspects an EVAP system leak, it quickly illuminates the Check Engine Light.
  • Slight drop in the gas mileage with the EVAP leak: If the EVAP vent solenoid and EVAP purge solenoid do not open as they should, your gas mileage may suffer. The combustion vapors in your vehicle will be vented via the EVAP canister, using a portion of the fuel that would otherwise be used for combustion.
  • Fuel smell: Occasionally, you may also detect a fuel odor emanating from the engine due to leaking fuel vapor.
  • A failed emission test or smoke test: A failed emission or smoke test is one of the primary indicators of the P0442 trouble code. A smoke test is conducted to discover difficult-to-notice gasoline vapor leaks. Using a specialized smoke machine that applies pressure to the fuel line and smokes to make small leaks visible, is accomplished.

Is It Safe To Drive With a P0442 Code?

Yes, it is safe to drive with the P0442 trouble code because it doesn’t show any adverse symptoms. The P0442 trouble code is generally considered a mild code. Even though you cannot pass an emissions test with this code, typically nothing else will occur.

Nevertheless, the more troublesome issue is that you won’t be able to determine whether there is another underlying problem because the check engine light is on. In addition, the longer this condition persists, the greater the likelihood that it will advance from a moderate EVAP system leak to a severe one.

Even though this trouble code is not critical, you should nonetheless inspect your gas cap and, if it appears to be in good shape, take your car in for repairs as soon as possible.

How To Diagnose The P0442 Code

Here is how to diagnose the P0442 trouble code:

  1. Connect an OBD-II scanner to the engine and check which codes show up.
  2. Analyze the freeze frame data connected with the code, which indicates the vehicle’s conditions at the moment of the malfunction.
  3. Clear the codes and perform a test drive.
  4. Perform a visual assessment of the EVAP system, searching for visibly cracked or broken components and loose or damaged EVAP lines.
  5. Examine the fuel tank or charcoal canister for cracks.
  6. Inspect the gas cap for appropriate fitment and condition, then tested with a gas cap tester.
  7. Use a scanning device to monitor tank pressure and determine the presence of a leak.
  8. Examine the solenoids and valves of the EVAP system using a scan tool.
  9. Conduct a smoke test on the EVAP system, searching for smoke that signals a vapor leak.

Most Common Mistakes When Diagnosing The P0442 Code

Most people want to immediately begin diagnosing the EVAP system. They plan to conduct leak testing and expect the worst. In doing so, they overlook the simplest solutions.

For many people, tightening the gas cap is sufficient to clear the code. If you proceed directly to complex issues, you may waste money and time that are not required. Start with the easiest tasks first.

It’s also likely that you didn’t turn off the car when refueling, which will result in the P0442 code, which must be cleared with an OBD scanner.

How Much Does It Cost To Repair P0442 Code?

In the following, I will share how much it cost to repair the P0442 trouble code. These costs include labor and parts, so you may be able to save money if you do the work yourself.

  • Repairing the faulty EVAP system line: $75-$600
  • Replacement of the charcoal canister vent control valve: $150-$600
  • Replacement of the purge volume control valve: $150-$600
  • The fuel cap replacement: $20-$60
  • The FTP sensor replacement: $250-$500
  • The leak detection pump replacement: $150-$450
MakeP0442 CodeRepair Cost
ToyotaYes$75 – $600
NissanYes$75 – $600
ChevroletYes$75 – $600
BMWYes$75 – $600
AudiYes$75 – $600
BuickYes$75 – $600
MercedesYes$75 – $600
GMCYes$75 – $600
SuzukiYes$75 – $600
TataYes$75 – $600
LexusYes$75 – $600
MazdaYes$75 – $600
MitsubishiYes$75 – $600
KiaYes$75 – $600
JeepYes$75 – $600
FiatYes$75 – $600
HondaYes$75 – $600
HyundaiYes$75 – $600
OpelYes$75 – $600
FordYes$75 – $600
FiatYes$75 – $600
PeugeotYes$75 – $600

What Repairs Can Fix The P0442 Code?

Repairs that can fix the P0442 trouble code include:

  • Replace the damaged or loose gas cap.
  • Change the faulty canister vent control valve.
  • Change the faulty purge volume control valve.
  • Replace the fuel tank.
  • Fix the damaged EVAP system lines.
  • Replace the FTP sensor
  • Replace the bad leak detection pump.

How To Fix The P0442 Code

The only proper technique to resolve the P0442 trouble code is, to begin with, the proper diagnostic. We recommend that you follow the steps listed below to determine what repair is required.

Here is how to fix the P0442 trouble code:

  • Tightening or replacing the fuel cap.
  • Replacing the faulty canister vent control valve.
  • Replacing the faulty purge volume control valve.
  • Fix the damaged fuel tank.
  • Fix the damaged EVAP system line.
  • Change the fuel tank pressure (FTP) sensor.
  • Change the leak detection pump.

In Conclusion

While many trouble codes are cause for serious alarm, the P0442 trouble code is not one of them. In most cases, the problem is straightforward and there will be no drivability difficulties.

Yet, you should never ignore anything that causes the Check Engine Light to illuminate.

Make time to do diagnostics as soon as feasible and repair the defect so that the light can be turned off.

Not only will you feel better about your car’s condition, but you’ll also know you’re helping the environment. You will also not have to worry about failing your next emissions test.



Vide Polowenski, Senior Mechanic

The information in this article is current and up-to-date in accordance with the latest mechanic SOPs.

Please take the time to leave a comment if this article has helped you in any way, you need additional help, or you have a suggestion.

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