Reseting DTC's
 

This one is for you Captain since you have to know how it works to know why its not.Ever since the length of time it took to reset the evap system the first time during the cold months I have been Leary of resetting a DTC with a scanner tool because it resets all the IM'S when you do correct. That's rite isn't it but if the repair is done correct then the DTC won't come back.

From my knowledge, after the issue is "fixed" (only quote that just in case its not) the DTCs need to be reset. They will not reset on their own. (if I am gathering what you are asking correctly)

And if the problem is still there, the code will come back and the CEL will come back on.

Dtc Resetting
 

Thanks for the answer Richphoto,s I have just been worried about the reset with a scanner because it usually resets all the IM,s and it just took me about three months to get the evap system to reset but I believe it may have been because of the cold.

If you clear the DTC's, all of the monitors will also be reset. If you don't clear the DTC's, and all of the problems are correctly repaired, the DTC's will eventually clear from the history file.

The reason for clearing DTC's after a repair, is so you can perform a drive cycle and verify that the repair was done correctly, and that there are no other faults in the OBDII system.

Think you may still have problem with EVAP system, if its taking that long to complete.
I know EVAP standards get tougher in later models. You need to find out exactly how test is run for 2003, then find where your DTC fits in the 2003 sequence.
MIL will shut off soon as EVAP completes ready test. Believe system seal and flow tests only take 1 or 2 cold starts. DTC will remain in history for 40 cold starts I think.
My experience With IM Mode6...
My 98 Envoy was parked for 4 years.
Mice chewed through VCM wiring harness.
Made couple of wiring errors trying to get her started.
Mega DTC due to wiring errors...
(MIL stays on due to wiring issue, VCM is not commanding MIL on)
Didn't do General Motors Drive Cycle.
Just a week of driving to work, errands and test drives, IM completed within a week after getting wiring sorted.
My 96 Blazer took forever to clear P0440.
Summer time MIL didn't come on.
Once cold weather set in MIL would illuminate intermittently and take long time to shut off.
Turned out that fuel filler pipe was getting rusty and developed rust track between rubber hose and pipe.
Changed out filler & vent pipes and new marine grade hoses no more codes!

DTC,s
 

Thank to all for answers it makes it so much better to be able to do and check the things mentioned and probably do a quick lasting repair.Thanks guys for the info.

This one is for you Captain since you have to know how it works to know why its not.Ever since the length of time it took to reset the evap system the first time during the cold months I have been Leary of resetting a DTC also I thought I remembered you saying you didn't have to if the fix was good it would just take so many start ups to reset itself.But with a scanner tool it resets all the IM'S when you clear the DTC. That's rite isn't it but if the repair is done correct then the DTC won't come back.Sometimes it takes two or three ignition on,s I had a little DTC booklet from Innova that had a chart that told what each code required to reset on its own if the fix was done rite so you don't have to reset all the monitors unless you want to.