OBD2 @ Laptop Sniffer

[Weatheralls Auto]

Ok Gurus, I need some tips here.

I am looking to make a sniffer for the J1850 Vpw dataline off the OBD2 connector.

I am interested in logging what is sent to and from the Pcm
eg, if I am using my Elm device, I want the laptop to record info/requests sent to/from Pcm or if I am using my Tech2 I want the laptop to record info/requests sent to/from Pcm.

I know its possible, but have not found out how to do it yet?

Any tips? I am almost googled myself to death lol.

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[robertisaar]

what you're suggesting is identical to what i asked about with the Tech2 on a OBD1.5 setup...

basically, get a port sniffer and then you can see everything going in and out of a port. i had a decent one at one time, but couldn't get anywhere with it due to lack of a Tech2 to play with...

[Weatheralls Auto]

Ahhhh, I have Tech2 but no port sniffer lol

[Weatheralls Auto]

I have found this site, seems to have both Hardware abd software, but no prices which is scary lol
http://www.dgtech.com/product/dlm/dlm.php

[Weatheralls Auto]

So much info out there for European data, very little for NA GM, and one who do have some info are tight lipped as they make $$$ off it lol,

Sux, but I am still searching,

May have to try a few different devices, first step I guess is finding what the Ecm is needing to see in order to send out the "Seed"

[Weatheralls Auto]

dgtech product very nice, you could do SO MUCH MORE with it, like monitor Dataline and use tech2 to unlock doors or honk horn or any output test, you would then know the command and build a sweet little CarPuter.

Downfalls,
1, Would take quite some time interpreting all commands
2, 3,000 for Hardware & Software
HPTuners would be much cheaper if you just want to tune.


Now I have read that an Elm327 device is not capable of interpreting all these commands, but, now I have read where someone has used one.

So, I am currently writting some VB6 code to see if my Elm327 can do some of this.

About half way done making routine for getting Seed/Key ( any programmers out there want to help? lol I have a freebasic code that I am converting to VB6)

Now, this wont be finding the algo for seed/key just brute trial an error,

If I can get 2 requests (36/37) per 10 second slot, looks like max time will be 4 days lol.

However, finding enough Seed/Key pairs, should be able to find the Algorithm, No?

[Weatheralls Auto]

Maybe I am the only one interested in this, but, if I am successful at getting the seed/key pair, retrieving the ECU info, then actually being able to write file back to Ecu, with the help of Tiny Tuner to edit the actual file, there would be no need to purchase an expensive setup like HPtuners.
Basically a $30 cable from ebay and we would be all set to tune our OBD2 Pcms?

[robertisaar]

sounds like you know what you're doing...