P0442 Code: Evaporative Emission Control System Leak Detected (Small Leak)


Modern vehicles have an internal computer that controls the overall performance of your vehicle but, also indicates the error code P0442, that is generated by the faults in the components of the vehicle. When the particular check engine light illuminates it indicates that your vehicle is getting problems in the specific component.

Definition of the P0442 error code

The DTC generated error code P0442 states that Evaporative Emission Control System Leak Detected, which means that there are some faults in the evaporative system of the vehicle.

What does the P0442 error code mean?

The EVAP system of the vehicle prevents fuel emission to emit into the atmosphere. The fuel vapors are stored in the charcoal canisters which are absorbed by the charcoal pellets. The engine control module controls the vent control module and burns the gas vapor that flows from the charcoal canister to the engine air intake.


When we switch off the engine of the vehicle then ECM performs a leak test to check whether the EVAP is working correctly or not. During this test procedure, the ECM closes the vent control valve and purge valve to seal the evaporative system of the vehicle. If the EVAP system is not able to maintain the specific pressure, the ECM gets an idea of leakage in the EVAP system. Then P0442 errors are detected and check engine lights illuminates.

Possible cause of P0442 error code

There are various possible causes of the P0442 error code. Some of them are:

  • The gas cap is loosely fixed
  • Local brand gas cap
  • Leakage in vapor tube
  • Minor leakage in the EVAP system
  • Faults in vent O-Ring seal
  • Faults in vent valve
  • Faults in purge valve
  • Defects in leak detection pump
  • Leakage in the fuel tank

Symptoms of the P0442 error code

The symptoms of the P0442 error code are hard to notice. Some common symptoms of P0442 error code are:

  • Check engine light turns On
  • Drop-in gas mileage due to leakage in the EVAP system
  • Fuel emission increases
  • Foul odors

The severity of the P0442 error code

This P0442 error code does not have any adverse effect on the vehicle. You can detect this error code when the check engine light illuminates. The only bad effect of this error code is that there is leakage of the fuel emissions to the atmosphere. The fuel economy of the vehicle slightly drops.

How to diagnose the P0442 error code?

While driving when you feel some problems in your vehicle, as the first step, you should take your vehicle to the mechanic. When mechanics diagnose that your vehicle is triggered with the P0442 error code then, first of all, they will scan the DLC port of the vehicle to detect the error code with the help of the OBD-II scanning tool.
After scanning they will examine the freeze frame data to check that any other codes are present are causing the problems in the vehicle.


After the inspection of the error codes, they will reset the codes and take a small test drive to check if the error code P0442 returns.
If the code returns, next they will check the EVAP system to find out the cracks, broken components, or any loose EVAP lines.
After repairing or replacing, if the code remains, they will go further for the inspection of the cracks in the fuel tank or charcoal canister. If they found any cracks in the charcoal canister they will repair the crack.
After the charcoal canister, they will inspect the gas cap with the help of a gas cap tester. They will look for the leakage by monitoring the tank pressure.
After performing the test with the gas cap, the code remains, then they will inspect the EVAP system solenoid and valves with the help of a scan tool. The smoke test is done to check the vapor leakage in the EVAP system.

How to fix the P0442 error code?

After a diagnosis of the problems that cause the generation of the P0442 error code, the following steps are performed to fix that error code:

  • Replace or repair the gas cap
  • Replace the fuel tank
  • Replace the charcoal canister
  • Replace the EVAP system line
  • Replace the purge or vent lines

If your vehicle is diagnosed with the P0442 error code, it is recommended that take your vehicle to the mechanic and repair it as soon as possible.

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