07 Trailblazer, Write Failed.

[gman4dx266]

So i just hooked up to our brand new 07 tb, and the write cal. failed on me, saying something like a packet missing or dropped or something. So i tried a write entire and that failed too, and told me not to pull any fuses. The thing is, it dawned on me after it told me that, that its got XM and Onstar. Id -like- to pull the fuses for those(where are they on the TB, btw?) but i didnt wanna disobey what the VCM Suite told me about not pulling any. should i do it, and if not, what can i do? Its under warranty, so i can just claim it was a lightning strike closeby or something.

[gman4dx266]

I pulled the radio fuse, and unplugged the onstar. Write calibration and Write Entire *both* give me "Unknown Error 8A"

pleaaaaaase help.

[Keith@HPTuners]

Whats the exact message in the status line of the flash form?

[Chris@HPTuners]

disconnect the battery for a few mins, also disconnect the MPVI from your PC. connect everything back up and then try a write entire.

Chris...

[gman4dx266]

Keith, i have no idea what you're talking about...but all it says was "Unknown error occurred. Error 8A"

Chris, is it really safe to disconnect the battery? I mean, i trust you and all, but the vcm suite told me to not even pull fuses.

Also, everytime i try either type of write(highspeed or lowspeed) it does go into recovery mode...i assume thats a good thing.

Its cold out now so ill try the battery trick tomorrow.

Heres my stock file, just for kicks...maybe it will help, who knows.

EDIT: Perhaps i can try this too.>>> http://www.hptuners.com/forum/showthread.php?t=5851

[EC_Tune]

You can't kill an LS2 (05 or later) style PCM. So Chris is correct. GM put a bootloader in there that is "protected" so the PCM will always come back to life.

[gman4dx266]

Well, i did what you guys said, pulled the battery and onstar/XM fuses. Did a write cal, and it went thru in 30 seconds or so, like usual. and said successful.
still wont start. tried to do a write entire, no-go. I still get that Error 8A, then a popup that says dont pull any fuses, yadda yadda yadda.

So now what?

EDIT: Oh yeah, and i tried that turning the key off after the bootloader gets in...that...didnt do anything. And when i do the write entire after pulling the battery and fuses, it gets all the way down to where it erases the VCM, and the progress bar gets about right under the M in VCM and then times out/fails.

[Keith@HPTuners]

Please take a screenshot of the error 8A. Make sure the vcm write form is also visible.

[gman4dx266]

I get that 8A sporadically...Ill see if i can do it again.

[Keith@HPTuners]

If the write entire failed at any point, you need to do a write entire to recover.

[gman4dx266]

This thing is driving me nuts! i cant get the 8A now, but heres 4 screenshots of 4 different things it told me.

Ill paste the links, since otherwise they'd be huge(my screen is 1280x768, so it'd suck for other users to have 4 of those together)

3 of the 4 are write cal's. I had another one of a write entire, but i have no idea where it went. It was the same though, it said failed, but then said check vehicle power/vcm power not found.

[Keith@HPTuners]

Few things...

Close down any additional programs you may have running. Your laptop may not be able to keep up with communications if its very bogged down.

Try a different USB port.

Try new USB and OBD cables. Your current cables may be failing.

Intermittent issues are almost always the result of one of the above causes.

[gman4dx266]

Ive tried a few different USB cables...and also, went over to our 1500HD and put a new cal right into it without a hitch. I also have nothing else running in my tray or in the background(since i dont believe in virus protection or firewalls :-P)

Looks like someones gonna be callin 1-800-CHEV-USA

Is there a patch or something i can use to just stick the above said bootloader back in, and get it atleast 1/2 way decent? lol im sorry i really have no idea what im talking about, but i was just wondering.

[Keith@HPTuners]

Ok, so you've isolated it to this specific vehicle.

Could be a noisy or faulty module on the communications bus which is causing interruption.. or a wiring short, or bad wiring..

[gman4dx266]

Electronic stuff is great, but its a bitch when it doesnt work. Like i said before, i pulled onstar(and even pulled the connectors out of the actual onstar box under the rear seat) and pulled the radio fuse. What else is there on the system bus that could be the culprit. Thats almost what it seems like to me, since you guys say you cant hose an LS2 based pcm.

Anything else i can pull?

[Keith@HPTuners]

could be abs, traction control, etc....

also check your obd port, make sure it looks clean and no wires look frayed.

[gman4dx266]

It does have stabilitrak, perhaps thats it. I didnt see that fuse under the seat, so its under the hood if anywhere. Ill pull that later on sometime or tomorrow and see if i can get anywhere.

[Keith@HPTuners]

No need to unplug the modules themselves, pulling fuses should be all you need to do (if its a faulty module).

[Power_Adder]

Well, i did what you guys said, pulled the battery and onstar/XM fuses. Did a write cal, and it went thru in 30 seconds or so, like usual. and said successful.
still wont start. tried to do a write entire, no-go. I still get that Error 8A, then a popup that says dont pull any fuses, yadda yadda yadda.

So now what?

EDIT: Oh yeah, and i tried that turning the key off after the bootloader gets in...that...didnt do anything. And when i do the write entire after pulling the battery and fuses, it gets all the way down to where it erases the VCM, and the progress bar gets about right under the M in VCM and then times out/fails.

I had the same issues on my 06 TBSS. Nothing worked and had to take it to the dealer. The work order and service advisor said they had to replace the PCM, and they did not know what caused the problem.

I never new why this happened...and could not offer any more information to Keith to help determine the cause. I understand the PCM cannot be fried, but obviously something went wrong with our 2 PCMs (my SS was manufactured 3/2006). Perhaps just a screwy glitch....guess our PCMs were made Monday morning after a weekend of heavy drinking?

Anyway, like I said, they replaced the PCM and I have done a few tunes with the new PCM and all seems well.

Goodluck.

oh, and btw, when I took it to the dealor....all I said was "Wow, I came out to go to work and the truck just would not start." Warranty covered everything.

[gman4dx266]

on the phone w/ GM. gonna get it fixed. Nothing ive tried worked.