I've scoured the internet in search of an open source PCM flash tool. The closest i've come to seeing one was made by planethax (with help) on this site. I've gathered a treasure trove of information regarding GM obd2 VPW protocol and the intel 28f400B but haven't been able to get my bin. That said, please help gurus and weekend warriors alike.
First here's what i've been working with OBDallinone elm327 USB, hyperteminal, Putty, a 2002 411 PCM, and open knowledge from everyone whos posted on a forum in the last 10+ years. Truthfully my intention is only to remove VATS (for now).
Heres the HYPERTERMINAL setup, putty of course is the same. User beware this can be tricky also don't bother messing with this unless you have your seed/key and are totally prepared to buy a new PCM. If your new to this I highly suggest you read http://elmelectronics.com/DSheets/ELM327DS.pdf .
Baud 38400
parity none
Data bits 8
Stop Bits 1
Flow control none
To set the elm to high speed use ATBRD with a devisor of 23 and this will give you 115200 baud.
Here's the supposed procedure for a upload from the 411 PCM to a device (but it doesn't work) any suggestions? Also not sure what PCMs this works on.
AT RV — CHECK VOLTAGE (MAKE SURE ITS 12 VOLTS. MULTIMETER AND CAL. IF NEEDED)
AT SP2 — SET ELM TO J1850
AT H1 — SET HEADERS ON
AT SH 6C FE F0 — SET HEADER
3F — TEST DEVICE PRESENT RX(NO DATA) why no data?
AT SH 6C F0 10 — SET HEADER TO
27 01 — GET SEED RX(6C F0 10 67 01 66 7E 52) your seed will be different
27 02 14 E7 -- SEND CORRECT KEY RX(6C F0 10 67 02 34 4B) your key will be different
AT SH 6C FE F0 — SET HEADER
3F — TEST DEVICE PRESENT RX(NO DATA) why no data?
AT SH 6C F0 10 — SET HEADER TO
A1 — REQUEST HIGH SPEED MODE
You only have a short time before it returns to normal speed automatically <5 sec.
AT SH 6D 10 F1 --
36 00 00 80 FF 80 00 — (eg. 128 bytes, start loc FF8000)
after failure or success make sure to do this
AT SH 6C F0 10 — SET HEADER TO
A0 — RETURN TO NORMAL MODE
AT D — RESETS ELM