txperformance

I have been a member of this forum for a long time now but this is my first post. I have learned a LOT of valuable info from this site on previous builds and i hope to get some insight or suggestions with a problem im having right now.

I have an '01 Yukon Denali 6.0 pretty much all stock programmed w/ Hypertech PP3 and it's been running great for over a year. A couple days ago I hooked up the programmer to adjust my tire size and now the truck wont start.. it cranks and runs for a second then seems like the ecm shuts off fuel. Please note I have had Passlock issues in the past but i bypassed it about a year ago and ive had zero issues since. I would otherwise diagnose this as being a VATS issue but the security light is NOT illuminated, not blinking or anything with the key on. It only blinks with the door opened and turns off when the key is turned on. I've tried everything, unhooked the battery, reprogrammed to stock, tried a security relearn 3 times and nothing is working. I did not have any trouble codes when i scanned it either... Im thinking the ecm might be screwed up because the truck was running absolutely perfect before i parked it and hooked up the programmer. I been wanting to get the passlock and on-star deleted from the computer anyways (if that's possible) and get custom tune. Is it worth it to invest in HP Tuners? Should I send the ecm off to a professional tuner or should I just get a dealer re-flash? Im very good with electrical & wiring and im usually pretty good at figuring these things out with the help of forums and such but this issue has me stumped... Any help would be greatly appreciated!

P.S. i also called Hypertech and they basically told me the tuner is "outdated" and there is nothing they can do or recommend for me, but they insisted it is not an issue with the program! Even though the truck was running great before i plugged it in...

BLK02WS6

iTrader: (2)

Hard to say exactly what happened. Maybe try to find a tuner near you who can do a full flash of a stock tune and change the gears for you. They will be able to tell if the PCM is trashed or if it just got put in a deadpole state when they try to push to it. I would say dealer, but since you need your gears programmed, might as well get a tuner to look at it.

txperformance

Whats even more confusing is my handheld DTC scanner will communicate with the PCM, it reads the vin# and checks for DTC's & such... The Hypertech tuner also acts like it's communicating, even turns on dash lights, fuel pump, etc. when it's doing it's thing, says tuning complete and everything... engine just wont run now. I wish there was some way to see whats going on in there but im limited as to what parameters i can see because i only have a handheld DTC scanner ($159.99 O'Reilly's special)... Is it possible my PCM is completely fried or do you think i could just get it re-flashed with a custom tune? I dont know of any local tuners (FW, TX) and i really dont want to tow my truck anywhere, i'd rather just pull the PCM out and take it somewhere or mail it if i have to...I want to get a custom tune and i've been contemplating just biting the bullet & buying EFI or HPT and learning the ropes for future projects ... just not sure what to do!

BLK02WS6

iTrader: (2)

The PCM isn't fried from what you describe in the last post. That is a strange one... Could be a memory problem in the hypertech handheld. If you get a tuning suite, you can find out by flashing a new tune into it...

kbracing96

iTrader: (26)

Yeah, it isn't fried. It really sounds like a VATS issue. If you wanna get EFILive, I'm a reseller for them. It's $899 shipped, just let me know.

Suburbazine

I had a similar issue with a Hypertech on a 2002 PCM. The tune crapped out in a parking lot for some reason and it took me 3 reflashes to get the PCM to let the truck start.

txperformance

Did you re-flash it with the Hypertech handheld or did you have to take it to the dealer?

nonnieselman

iTrader: (10)

Years ago i had that style issue. Pulled up to a gas station to get some gasola. reflashed a updated tune with EFI Live and it would start then die. I started flashing in old tunes till it cranked. Then flased in the first tune i was goin to put in it. And it was fine. Never done it again. so who knows.

Suburbazine

Just kept hitting it with the handheld. Magically worked about 45 minutes later and ran without a hitch until I got it tuned with HPTuners.

txperformance

Hell I tuned to stock & retuned it over and over for about 8 times with no luck... I just went ahead and bit the bullet and ordered HPT, should have it by Tuesday. Needless to say, I have a lot of reading to do!