04-12-2009, 07:01 PM
Hi Everyone, I was wondering if there is some way to read/flash the ecu using a pc only with some kind of diy interface instead of having to get one of those 400$ ecu flashers? I mean, we are able to flash the programmable rom for pretty much any hardware that exists (most electronics does have a jtag port of some sort on their board), so why couldn't be a way to emulate what does expensive flasher do with a laptop with some kind of OBD2 interface!? Im pretty much a newbie when it comes to mechanic (im learning though:)) but ive been working in computer for over 10 years and I know my way in electronics but I am not aware of any software and interface besides the reader for obd2 codes, so I tought maybe someone over here can help :)
04-13-2009, 01:15 AM
as far as I can tell its a half-duplex twisted pair communications setup like RS485, but its called CANbus (controller area network). In the simplest CAN system you send 8 bit slices of data inside of longer 21 bit chains containing start, stop, CRC, and some other junk.
once you figure out the communications then you have to crack the hex dump of the eeprom. find out which tables are where, etc.
then you can start making tunes.
There is one person I know of on this forum doing this, but i forgot his username...
04-13-2009, 01:26 AM
oh and even once you do get that figured out what are you going to do for datalogging? lots n lots of wiring and setup and work to be done just so you can see what is going on.
04-13-2009, 01:32 AM
another way you could do it is remove the eeprom and use the J3 port.
04-13-2009, 01:44 AM
I think all the time and hard work you'd have to put in plus the risk of messing stuff up is well worth the $400 tom charges for a flasher and his tune. Just me .02
04-13-2009, 07:59 AM
Ultimately it's not worth it. As has already been said, if you figure out the flashing you would then have to find the tables, their size, limits, etc to be able to change anything. Reverse engineering like this takes a long time.
illinipo: CAN bus is used on the focus 2005+. Prior to that they used SCP which is completely different.
04-13-2009, 07:54 PM
thanks for all your replies, I am aware that this will be an extremely complicated project, I will start by reading those links (thanks illinipo) and I will eventually start to experiment. I know that in the long run it might not be worth it considering the amount of time that will be needed to be spent working on this but I think that it would still be a nice project to work on, I wish these were open source it would take a whole lot less time heheh :) it would be nice to be able to datalog all the time and be able to flash the ecu almost on the fly :)
04-13-2009, 07:54 PM
also is SCP less secure than CAN?
04-13-2009, 08:14 PM
here you go man
Standard Corporate Protocol:
04-13-2009, 08:59 PM
^ This guy's just too freaking good!
04-13-2009, 09:08 PM
Just wait till I open up my tuning shop [;)] lol