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

How to easily diagnose, repair, and info on causes of a P0442 trouble code which indicates a small EVAP emissions leak has been detected.

Symptoms of P0442 OBD II Trouble Code

  • A loose or improperly affixed gas cap
  • A non-conforming gas cap (i.e. not factory/original brand)
  • A small leak/hole in a fuel vapor hose/tube
  • Other small leak in EVAP system
  • Faulty vent o-ring seal
  • Defective vent valve
  • Defective purge valve
  • Defective leak detection pump

Common Causes of P0442 OBD II Trouble Code

  • Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
  • Otherwise, replace the gas cap (we recommend an OEM original part, not aftermarket part), or
  • Visually inspect the EVAP system for cuts/holes in tubes/hoses