Get 5% off in-app
400k+ download
Open app

P0442 Code: How to Fix It? All Questions Answered from Causes to Cost!

Spread the love

If you drive cars, you might likely have come across the P0442 code. Although it is not something to be seriously worried about, you can’t simply neglect that either, as it can take a toll on your car’s fuel efficiency. Today, we’ll find all answers to your P0442 queries in this article. 

The P0442 is an OBD-II code that indicates an evaporative emission control (EVAP) system leak. It is not a very serious concern as far as the short-term drivability of the car is concerned, as you can keep driving your vehicle for a few miles before getting it repaired.  

Save around $1,850 annually on your auto refinance!

That being said, the P0442 is not something to be totally neglected either. If ignored, it can make your car an excessive drinker, i.e. It can lead to high fuel consumption. 

The number P0442 means a “small EVAP system leak.” Your ECU checks the liquid emissions system for big and small holes at an engine start-up. To do this, it fills the system with pressure and then looks for any drops in vacuum pressure.

What is the EVAP system? 

The Evaporative Emission Control (EVAP) system is installed in a car in order to keep fuel vapors from escaping into the air. This is made possible by absorbing these vapors and storing them in charcoal pellets inside the charcoal canister installed within the car. 

Two control valves help in this process. One is a Vent Control Valve which controls the flow of vapors using the Engine Control Module (ECM) of the car. The ECM opens the vent control valve, which lets air into the charcoal canister, where it’s burned together with any remaining gas fumes before the air enters the engine. In addition, A purge volume control valve regulates the rate at which gas vapors escape from the charcoal canister and enter the engine’s air intake.  

The vent control valve is open during normal engine operation. The purge volume control valve is active when the engine control module (ECM) is ready to burn off the accumulated fuel vapors. Overall, this helps the car to emit less.  

The ECM performs a leak test to check that the evaporative emission control system is operational. This is by shutting the vent control valve and the purge valve during the leak test to seal the evaporative system. The ECM detects an evaporative emission control leak if the EVAP system fails to maintain pressure. This leads to the P0442 code indication.

P0442 is a medium-sized leak measuring up to 0.040″ in diameter.

What are the causes of P0442?  

Some of the reasons behind the P0442 indication popping up are:  

  • A damaged or improperly affixed gas cap. (possibly an aftermarket gas cap that fits loose) 
  • A leak/ hole or disconnection of the EVAP hose  
  • Leakage in the charcoal canister  
  • Fuel tank leakage
  • Damaged vent control valve 
  • Damaged purge volume control valve 
  • Defective vent valve  
  • Purge valve malfunction
  • Defective leak detection pump 

How to fix a P0442 code?

You can fix the P0442 code with the following methods:

  • Putting on a new gas cap or putting in a new gas tank
  • Changing out the charcoal container
  • Putting in new lines for the EVAP system
  • Change the air or purge valves

With an ODB II reader, you can clear the code. It should also work itself out after a few drives.

Diagnosing P0442 code 

P0442 code repair
Photo by Sten Rademaker on Unsplash

Besides the check engine light being illuminated to indicate the P0442 error, drivers can notice an unusual fuel odor and a drop in the fuel economy of the car if there is an issue with the EVAP system. In addition, the car will also return high values on an emission test in this condition.  

Though a P0442 error does not affect your car’s drivability, we recommend you resolve it as soon as possible to avoid potential damage.  

What should I expect to pay to fix a P0442 error? 

As discussed above, the P0442 error can arise due to various damaged components and mismatches, like defective valves, incompatible gas caps, and fuel tank leaks. Having said that, the cost of fixing the P0442 error depends upon which of these parts have to be fixed. This can only be ascertained after a thorough vehicle diagnosis by a mechanic. However, A diagnosis can set you back by approx $70 – $150, after which they’ll fix the required part for you. 

The cost of the parts to fix the P0442 error can range between $10 to $600. Some parts and their costs are: 

  • Gas Cap: $10 to $100 
  • Purge Control Valve: $160 to $181 
  • Vent Control Valve: $150 to $200 
  • EVAP lines: $50 and above 
  • Fuel tank pressure sensor: $40 to $300 
  • EVAP canister/ Charcoal Canister: $150-$600 

Having said that, you can even save some money by finding usable parts from a junkyard at a fraction of the price of a new one.

Can you diagnose code P0442 at home? 

There is no one-solution-fits-all for diagnosing the P0442 code on your car, as diagnostic procedures depend upon the car’s make.  

You can try rectifying the P0442 error code yourself if you’re confident enough and don’t want to spend on expensive repairs. However, note that this is not a task for novices since it requires some expertise to diagnose and repair. If you have basic to intermediate knowledge regarding the working of automobiles, you can try the following: 

  • Remove and replace the gas cap, drive for a day or two after clearing the codes and observe if the codes pop up again 
  • If the issue persists, consider replacing it with a new original gas cap 
  • Inspect the EVAP system for holes or cracks in hoses 

In case you’re adept at vehicle mechanics, you can try the following:

  • Do a smoke test to identify where the leak is 
  • Consider performing an EVAP leak test using a scanning tool 
  • Inspect the EVAP purge valve/solenoid 

Is it OK to drive with the P0442 code?

You can drive if you have a P0442. But remember that your gas mileage will decrease, and your car will give off more pollution.

Taking care of your car expenses 

In situations like this, you start bothering about the expenses surrounding your car. However, the good news is that you’re not too late. Head to Way.com to find the best car services, insurance, and more deals! 


Here’s more info on top-rated airport parkingthe best parking spots in your city, affordable auto insurance, easy auto refinance, and high-quality car washes near you.

Related Posts


Press ESC to close