Scion XB P0442

My wife has a 2005 Scion xB that keeps throwing a P0442. I have replaced the gas cap and did a smoke test but nothing seems to be stopping this code being thrown every few days. To make matters worse, when the check engine light comes on it throws the car into a “limp” mode and decreases the performance and gas mileage. Most of my mechanical knowledge comes from my DIYing on my Ford Ranger and Vulcan motorcycle, so I am not too familiar with Toyota. Does anyone have a checklist of things I should be checking so I can put this issue to bed?

Possible causes of a P0442

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

That is a list of possibles. Cracked hoses can be very hard to find. Not sure why a smoke test didn’t find the problem. Also never heard of this code forcing limp mode

Maybe another poster can add some more Toyota info to help.

Me neither, but was researching a car that disabled the ABS when check engine light came on, I don’t know what it was but who knows what they do sometimes. I would have it scanned with a more comprehensive scanner though, to find out why it is in limp mode.