Blog - DTC Decoded: Dodge P0442

Diagnostic code: P0442

Make: Dodge

Decode: Leak Detected in the Evaporative Emission Control System

Code detection:

EVAP System

The PCM has indicated there is a small leak in the EVAP system. The leak may be less than 0.04 inch in size.

Symptoms of this code:

  • The Check Engine Light will be lit.
  • There may be a possible fuel odor.
  • You will not notice any drivability issues.

What causes this code?

  • The gas cap may be loose or not an original cap.
  • There may be a small leak in a fuel vapor hose or tube.
  • The EVAP system may have a small leak.
  • The o-ring seal to the vent may be faulty.
  • The vent valve or the purge valve may be defective.
  • The leak detection pump may be defective.

Dodge Code Description:

  • P0442

It is the job of the powertrain control module (PCM) to test the EVAP system for leaks. With this code, the PCM has determined that there is a small vapor leak within the system. It can be a tiny hole that you may not be able to see. The EVAP keeps the fuel vapors from escaping the fuel system. Those vapors travel through hoses to a charcoal canister where they are stored. While the engine is running, the purge valve opens up and allows the intake vacuum to draw out the fuel vapors into the engine.

What the techs say:

  • The most common way to repair this code is to remove the gas cap and reinstall it. You may need to replace the gas cap with an OEM part if the light does not go off after reinstalling the gas cap and driving a day.
  • Check the hoses and tubes of the EVAP system for cuts or holes.

If these common fixes do not help, you may need to do repairs that are more advanced.

  • Use a scan tool to do a leak test on the EVAP system.
  • Check the purge solenoid or valve on the EVAP system for defects.
  • Use smoke to see the leak.