I drive a 2004 GMC Sierra daily driver with a stock 5.3 and 4L60E tranny. I have had this problem the past year and now this year for my inspections. My truck is not modified besides the flowmaster muffler I welded on years ago...

The inspection sheet says:
1. 02 Sensor (NOT READY)
2, Evap (NOT READY)
3. Catalyst (NOT READY)

I have tried resetting my computer twice now by undoing the battery terminals and then driving the mileage. Both time i drove 300+ miles and still fail for the same reason...?

WHAT IS WRONG?! ANYONE ELSE HAVE THESE ISSUES?!

 

Are you its not tuned and the cats and rear o2's were deleted in the pcm?

 

Oh yeah im positive, my father and I have owned the truck since 2004. Bought it brand new. We build custom classic cars and do some LSX swaps and pro touring chevelles and camaros. But have never had this problem before seeing that classics only have safety inspections no computer hookup...

 

"Not Ready" means that you're going in for the test too soon after clearing the DTC's. These OBD2 vehicles have readiness moniters.

 

We drove for over 200-300+ miles after the first failing test and even disconnected the battery before driving that distance. Many people say they have these problems and just can't quite pin down the problem. ive done the freeway driving and its even 30 degrees here. (for the cold start portion of the testing) And im still getting theses things.?

 

Right. Quit disconnecting the battery and quit clearing the codes. If your Check Engine light is coming on, fix the problem. There really isn't a way around the system, that's why it's like that. You can thank the GOV for that. Bottom line is, it's failing for a reason. Figure it out and fix it.

 

Yeah i understand what you are saying but i have no codes or check lights coming on. and how am i supposed to pin down the problem if there is nothing to base it off of?

 

Any chance you can read the PCM with HP Tuners or EFI Live, and post the file here?

 

If you have access to a scanner go into mode $6 it may not throw a code but will abort running the rest of the monitors if there is a threshold min max value out in mode $6 it will say pass fail min max value. Also google GM drive cycle follow it accordingly to run o2 heater monitor engine needs to be cold start in morning turn on headlights and heater blower


http://service.gm.com/gmspo/mode6/