evap system

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I have a 99 Blazer that has a code 440 evap system. No other info was given on the scan. Where do I start to look?

posted by  hmwolf

when the truck starts the evap system will pressurize the fuel system check for loose gas cap(seal) and for leaks in the vapour lines if the ecm dosn't see the pressure it will turn on the engine light

posted by  osborste

I have the same problem with 1999 escalade. I bought a new after market gas cap and after 500 miles the same code came on. I then had a "smoke test" done and that was really inconclusive although they said they smell a little gas from tank seal. Now they want to pull the gas tank and see if that takes care of it. Any suggestions. Any chance an original equipment gas cap may do the trick. I hate to throw in $350 to have them pull the gas tank and still not find the problem. Getting to the point that piece of black electrician tape over the idiot light would be best solution.

posted by  gopher78

try it with a dealer cap it worked before cheaper than dropping the tank aftermaret stuff is ok but something are better at the dealer strick oem specs

posted by  osborste

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