04 Smog Help

Ok so trying to get my 04 smogged, when we take it to the smog station the guy is telling me that it won't read the computer. Just installed new battery and he says I need to drive a consistent 100 miles to get the battery to reset and make it possible to read the computer. Has anyone heard of this, or know what is going on and why it will not read the computer? I have had this happen two places? Thanks for the help.

Fuel trims need to be learned after power is lost. Drive it for a week and then take it back for a smog.

//2000CAYukon

Fuel trim should be relearned almost immediately. You need to drive it long enough for the EVAP monitors to run, which can take a while, it only does it under perfect conditions. Of course I don't remember them all, but ECT has to be within so many degrees of IAT at startup, and both have to be above and below fixed numbers. Fuel level has to be in a certain range. I want to say 20%-80% is in range, I think it's "teens" to "ninety something". I know the Tech-2 scan tool can force the test (great for verifying an EVAP leak fix), but I don't know if that makes the PCM show it as passed for emissions purposes. It can take several weeks for it to run on it's own. I'll try to remember to get the list from work for you, but it will be Tuesday.

Ok so trying to get my 04 smogged, when we take it to the smog station the guy is telling me that it won't read the computer. Just installed new battery and he says I need to drive a consistent 100 miles to get the battery to reset and make it possible to read the computer. Has anyone heard of this, or know what is going on and why it will not read the computer? I have had this happen two places? Thanks for the help.


if the battery was removed it is correct that this needs to be driven a few miles of hyway / back road to ensure its ready for testing..

the other issue if it is ,,,with your vehicle, is lack of communication with the test fixture and your vehicles computer...check all fuses especially the power ports that are on your dash panel,,,its strange but this circuit is part of the test port that the test fixture plugs into...no pwr here and no test data is received..

All of these guys have practiculy the right answer.