P0442 Code: Meaning, Causes, and Symptoms | OBD2 Codes

P0442 – Evaporative Emission Control System Leak Detected Small Leak

P0442: What does it mean?

The Codes P0442 indicates that a small leak is detected in the Evaporative Emission Control System(EVAP).

The EVAP is designed to prevent your gasoline vapor from leaking into the atmosphere. It is monitored by the Powertrain Control Module(PCM), and the computer will notify a DTC P0442 when a small leak is detected. Similar codes are P0455 (EVAP control system leak detected large leak) and P0456 (EVAP control system leak detected very small leak). All three codes have similar possible symptoms and causes, as well as simple fixes you can do yourself. Generally, P0456 and P0442 are more difficult to diagnose, as you can hardly see clearly cracked hoses or connectors. 

Severity: Low

Not important, as you mostly will not notice anything other than the engine light on. But it should be addressed as you cannot pass the emission test with it present.

Difficulty of diagnosis or repair: 3 out of 5

P0442 Possible Symptoms

As it’s a minor leak, P0442 will not always show itself except the engine light/service engine soon warning light on. Sometimes, you may notice a small fuel odor caused by the leak.

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Possible a noticeable fuel odor caused by the release of fuel vapors

P0442: Possible Causes

There are many possible causes for the code P0442, including:

  • Missing or loose fuel cap
  • Incorrect fuel filler cap used
  • Fuel filler cap remains open or fails to close
  • Foreign matter caught in the fuel filler cap
  • EVAP canister or fuel tank leaks
  • EVAP system hose leaking
  • Fuel tank leaking

Possible Checks/Fixes you can do yourself:

When you see a DTC Code P0442, there’re several checks you can do:

  1. Check the code from your OBD2 Scanner / Car Code Scanner and verify that it’s the only code present. If other codes are on the list, they should be checked first.
  2. If you have other codes such as P0441, P0440 or P0456, the issue might be a solenoid failure or a more complex system leak. Address these issues first.
  3. If Code P0442 is the only code present, check your gas cap to see if it’s open or loose. Tighten your gas cap will usually solve the problem. 
  4. After you tighten the gas cap, the engine light may turn off after several drive cycles. Refer to this article about the drive cycle. It will be completed mostly after a normal day drive.
  5. If the engine light doesn’t go off, inspect your gas cap for physical damage or deterioration. It’s not always noticeable, you can try to replace your gas cap as it’s not expensive. It usually will clear the codes P0442.
  6. If the fuel cap didn’t fix it, you should consider performing an EVAP system leak check. You can do it in most repair shops and car dealers. They will usually perform a smoke check through your EVAP and the smoke will show if there’s any leak from any hoses or seals. 

How much is the cost to clear P0442?

For car code P0442, several repairs may apply, and the cost estimations are below:

  • Replace the Gas Cap: $20-$60
  • EVAP Line: $20-$100
  • EVAP Vent Control Valve: $150-$200
  • Purge Volume Control Valve: $150-$200

Frequently Asked Questions:

Q: Can I drive with the code P0442?

A: Yes, you may drive your vehicle with Code P0442 unless you smell or see a serious fuel/liquid leaks.