A code P0442 most likely means one or more of the following has happened: 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
With a P0442, the most common repair is to: 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 (recommend an OEM not aftermarket part), or Inspect the EVAP system for cuts/holes in tubes/hoses More advanced troubleshooting steps include: Using an advanced scan tool, perform an EVAP leak test Verify operation of the EVAP purge solenoid / valve Perform a smoke test to see where the leak is Generally there are vehicle and model specific procedures for proper diagnosis of this DTC.
Read more at: http://www.obd-codes.com/p0442