Bricking LS1B PCM by Changing VIN

[minytrker]

I am not on the newest update, using V8 build 276 and V7.5 build 282. I have bricked 4 LS1B PCM's in a row by FULL flashing them to a different year (works every time) then using the scan tool to change VIN. Once I change the VIN the PCM is bricked. You can't read it or reflash it. I am changing 99-01 PCM's over to 2002 usually. I have done hundreds of these over the years and never had an issue until within the last month or two. I tried a different laptop, a new bench harness, new cables on my V2 and it still does it.

[GMPX]

Ok so in saying bricking are they totally non responsive or come back as locked? Technically bricking an ECM to the point of being non responsive by changing the VIN is impossible.
Also are these just standard OS's or custom OS's?

[minytrker]

Standard OS flashing to standard OS. Im flashing stock 99-01 PCM's over to 2002 12212156 usually. Today was flashing them to 2001 as a requested by customer. Once I full flash them I can read them back out or flash them again with zero issue. As soon as I take the Scan Tool and change the VIN to a 2002 or 2001 as in todays case I can no longer read or flash the pcm with efi or hpt. The pcm will also not run a vehicle either.

[GMPX]

I can no longer read or flash the pcm with efi or hpt. The pcm will also not run a vehicle either.
Ok, but what is the error that EFILive gives?

[minytrker]

19037

I'll get that or bootloader rejected.

[minytrker]

If I use V7 and check Try Alt Keys & Check Recover PCM I can FULL Flash PCM and it will take. So far got 3 of the 4 PCM's to work again using that method.

[GMPX]

I'll do some experimentation here, though I am of course using the latest install so it is not a 1:1 comparison.
I'll try going from 9381344 to 12212156. Regardless never heard of this issue before, absolutely bizarre.

[minytrker]

I also tried to flash my LB7 truck and it says its locked with custom key (even though its not). I can not read it or write it. After trying for 20-30 mins it now shows pcm is unlocked but still wont read or write. I updated laptop to Build 283 and it did not make a difference. I have not flashed my tuck in a couple years but I still have the same V2 and I never locked it.

Also noticed on the bench harness after changing VIN and trying to flash or read pcm it says recovery mode instead of the normal boot loader then unlocking before it locks up.

[GMC-2002-Dmax]

I had some strange issues with two LB7 ecms this week as well........bricked two of them on Full Flashes.

With no way to downgrade the V2 firmware and go back to an older software version I will have to roll the dice and see if it was a fluke or if it is a issue.

If I brick a third LB7 ecm today then I know something is up.

[minytrker]

Thats definitely not what I wanted to hear. I was going to mess with mine more today but I think I'll wait now. I cant afford to brick my ecm and have my truck down right now.

[GMC-2002-Dmax]

I did get a successful Full Flash today on an LB7, but I used V7.5.

When I read the file back out with V8 they usually match 100%, the read out file matched 99%, about 1/2 dozen tables has minor % differences in the tune editor doing a compare ??

This is all new things, after 9 years of flashing LB7's this was a weird week !

[Blacky]

If I use V7 and check Try Alt Keys & Check Recover PCM I can FULL Flash PCM and it will take. So far got 3 of the 4 PCM's to work again using that method.

There was a bug in an old version of the EFILive software/firmware that caused seed/key problems with LS1 and LB7 controllers, see issue #6 here https://forum.efilive.com/showthread.php?25502-Known-issues-with-May-01-2015-Public-Release

That bug caused the seed and key to sometimes get set to $0000 and $0000 respectively during a full-flash. That made the PCM appear to be locked and the only way to read or flash it from then on was to check the 'Assume Lock May Be Faulty" checkbox. To restore the seed/key, use the V7 PCM unlock option to unlock the PCM by specifying an unlock key of $0000.


Also noticed on the bench harness after changing VIN and trying to flash or read pcm it says recovery mode instead of the normal boot loader then unlocking before it locks up.

Changing the VIN should not cause any issues with the PCM. It should certainly not cause the "recovery mode" to be displayed on subsequent reads/flashes.

If/when you see the "recovery mode" displayed, that means when the read/flash was started the EFILive software could not obtain the VIN or operating system number of the PCM. That can happen if a previous full-flash aborted abnormally. In that case, EFILive's full-flash boot loader will still be controlling the ECM and the ECM can not report any data such as VIN or OS. In that case it is essential that you restart the full-flash process without removing power from the PCM.

In future if/when you experience issues like these, please, please send me (paul@efilive.com) the trace files so we can see what went wrong and suggest ways to prevent the failure in future and/or fix any problems in the software or firmware that may be contributing the the problem.

More information on locating the trace files:
https://support.efilive.com/kb_article.php?ref=8552-EOAJ-5912

Regards
Paul

[minytrker]

I updated to V8.2.2 Build 289 and was able to flash my LB7. I first tried with V7.5.7 Build 298 and it would not flash. It was not showing locked. Once I flashed it with V8 I did not try to flash or read it again with V7. I bought another LB7 ecm and am waiting on it before messing with mine again incase something goes wrong.

[Blacky]

I updated to V8.2.2 Build 289 and was able to flash my LB7. I first tried with V7.5.7 Build 298 and it would not flash. It was not showing locked. Once I flashed it with V8 I did not try to flash or read it again with V7. I bought another LB7 ecm and am waiting on it before messing with mine again incase something goes wrong.

I'm not sure I understand what the problem is. Can you explain in more detail?
Regards
Paul

[minytrker]

I also tried to flash my LB7 truck and it says its locked with custom key (even though its not). I can not read it or write it. After trying for 20-30 mins it now shows pcm is unlocked but still wont read or write. I have not flashed my tuck in a couple years but I still have the same V2 and I never locked it.

[Blacky]

I also tried to flash my LB7 truck and it says its locked with custom key (even though its not). I can not read it or write it. After trying for 20-30 mins it now shows pcm is unlocked but still wont read or write. I have not flashed my tuck in a couple years but I still have the same V2 and I never locked it.

If the NVRAM gets corrupted (and that happens a lot on the LB7 controller), then the seed/key will be corrupt. That will appear locked to all tuning software.
Try using V8 to read the controller with the "Try Alt Keys" and "Assume Lock May Be Faulty" check boxes checked. That will force the EFILive software to try a bunch of different key values that may get set when the NVRAM gets corrupted. If you can read it using those check boxes, send me the trace of the read and I can tell you what happened and hopefully how to fix it.

Best case - I can figure out the key and then you can unlock it using V7.
Worst case - the ECM will need to have the flash chip removed, reprogrammed and re-soldered to the main board in the ECM.

Regards
Paul