E54 Woes.........

[Lowlyfe1]

Little back story: A good friend of mine has a 2001 LM7, and he asked me if I could turn it up a little. I tried reading it out with HP Tuners and noticed the VIN at that point showed up as a bunch of garbage, and I was locked out from doing the read. "x35 unlock failed" was the code, I believe. The truck had an aftermarket radio, added electric start, and a few other things that made me think reading and writing in the truck was possibly the issue for the error. Anyway, I pulled the ECU out of the truck and tried reading it on the bench—same issue. HPT gives no log output, so at that point I hopped on GitHub and got the latest version of PCM Hammer and attempted to read it out. Same errors, but looking at the error logs, I see that the PCM was sending back an oddball 6-bit string vs. the expected 5-bit string for the seed key. I did a little more digging and found that I guess these ECUs are prone to "corrupting" themselves. I found another thread about the boot pin for the E54. Using the boot pin and on slow, I was able to enter programming mode with my J2534 cable and PCM Hammer, though it only got to 3% read and errored out after about 20 reconnect attempts. So I switched gears and hopped on the HP Tuners tune repository and got an original—or at least the closest—software version I could find. Also worth noting, from the reading I've done, they have 2 versions: Model year 2001 - Service No. 09388505 / Hardware No. 09355100; Model year 2002-2004(?) - Service No. 12210729 / Hardware No. 12209950. So with that being said, I would think that they have 2 different hardware versions? However, across several threads on EFI Live, HP Tuners, and a few other places, I've seen guys say they have cross-flashed 01-04 PCMs without issue, minus some small things like oil pressure/temp reading odd from cluster/PCM signals changing over the few years. Anyway, so like I said, I got a stock file from the HP Tuners site from a 2001, wrote the entire file, and all seemed to be good. The VIN was showing as it should, and port flashing was restored without using the boot pin. I went and reinstalled the ECU in the truck, and no start. I checked for codes, and none stored. So at this point, I'm kind of stuck and reaching out to the community hoping for some direction. VATS is disabled—triple-checked—and have rewritten the file a handful of times. Also tried cross-flashing a few other software versions, and same results. No start, and ECU has no codes and seems to be fine.
The original software version that was on the PCM was 15063376 and the current version I have on it is 15188873. Any input would be appreciated.

[Lowlyfe1]

Thinking about it, I did leave out one part. When I did the first complete flash using the boot pin, the VIN was still showing garbage, and the truck did start after that. The only problem was that the throttle did not work. The VIN started showing properly after doing a write of the VIN/seed key/VATS only, and it would not start, if that makes any sense?

[kur4o]

Did you try a vats relearn.

usually eeprom contains needed data for truck starting and that is now blanked.

Hpt seems complete garbage to brick it mid read. Maybe something corrupt communication in vehicle.

[Lowlyfe1]

Did you try a vats relearn.

usually eeprom contains needed data for truck starting and that is now blanked.

Hpt seems complete garbage to brick it mid read. Maybe something corrupt communication in vehicle.

Vats was disabled and security light was not flashing after crank or just with the key on. I was able to use PCM hamer on x1 write speed and 0000 as the seed key and finely I was able to do a full write. SO fair enough to say that this is a thread closed post as well as thanks to some other members having similar issues and documenting their findings, I was able to stumble through getting this thing back up and running.