Check engine lightcame on - had code checked at Auto Zone. It's P0442 ( Evaporative Emission System ). The guy at Auto Zone told me that it was a bad gas cap. New gas cap didn't work - anyone have any suggestions before I go to the dealer ?

 

Yeah thats the code that trips when you don't tighten the gas cap properly or else the gasket in the Gas cap is broken, causing the fuel tank vacuum to fall below a certain negative psi reading.

Did the guy at autozone clear the code or just read it?

 

He just read the code - didn't clear it. I tried to clear it myself by first pulling fuse to computer & then disconnecting the battery - I can't get code to clear

 

he just read the code - didn't clear it. I tried pulling fuse to computer and disconnecting battery - I can't get code to clear

 

The problem could be anything pertaining to sealing the evap system. Gas cap, Filler tube, fuel sender gasket, crack in the evap hoses, evap test port, evap canister, or canister purge valve.
This code sets when the system is not able to hold a vacuum for a specified amount of time.

 

You have to get it cleared when you get it fixed.

 

if you fix the problem the computer will clear the code itself but it may take some time like 50-100 miles

 

Hi Shawn, Is there a procedure to eliminate the possible problems you've described? That code popped on today in my 2000 blazer.

 

Most of the times I ran across this problem its been the canister vent solenoid thats mounted near the charcoal canister. Its not to costly.

 

There is a leak in the System as said before. I received this code prior to getting the correct code which was my evap canister and sensor. this is about a $1200 dollar repair from a dealer for my truck and i fixed it for $150 with the purchase of a code reader and eraser. Spend the 50 bucks on the code reader and clear them yourselves.