GM Lan Single Wire CAN Bus Sniffing

[SteveG8]

Ah - that's pretty sneaky! lol Nice

[foxdie]

Well, I've managed to capture packets of 90-95% of actions that can be completed with a dual zone climate control unit (from a Vauxhall VXR8 aka HSV Clubsport R8 E1). I'm now decrypting what each bit / byte does now.

I want to start adding data to the GMLAN Bible, I've dropped tmk a private message requesting read/write access, once the informations in there I'll post up a confirmation here

[foxdie]

The GMLan_Bible has been updated with some more info, and will continue to be updated as I sift through this data

[silversv6]

Hey guys, I would say you know what these are used for. can you enlighten me a little....Thanks, cheers
http://sailesmarketing.com/products/can ... interface/

[doubledip]

The CB28800 CAN Bus interface is designed to provide a vehicle speed signal for vehicles using a CAN Bus system

tells you right there will be reading the VSS PID on the HSCan and turning it into a usable speed output on a single wire... you buy these through holden as well... they have then for the VE commodore for TAXI's so they can get a speed input into their meters

[foxdie]

Hey guys, I would say you know what these are used for. can you enlighten me a little....Thanks, cheers
http://sailesmarketing.com/products/can ... interface/

Not sure this is the correct place for that question, but I'll answer it anyway. That module listens to vehicle speed data sent across CAN BUS (not specific to GMLan however) and outputs a vehicle speed signal (aka VSS, a pulse train to indicate vehicle speed) for connection to an aftermarket speedometer or another device that requires a VSS.

In short, it lets you use an aftermarket speedometer that isn't CAN BUS compatible with cars released within the last 5 years.

[foxdie]

Also worth noting, the GMLan_Bible has been updated yet again with information on HVAC (Climate Control), there's sufficient information there now to build a replacement HVAC controller so you can replace the god-awful head unit

I'm still adding more info to the HVAC entries (its a lot of effort sifting through the data, trying to work it out, major logic puzzle), but once it's complete I'll write a proof-of-concept HVAC Controller Replacement for mbed C++, which some other kind soul can probably translate to Arduino's Wiring programming language

Watch this space!

[silversv6]

Thanks, I just didn't realise that these later model cars don't give out a vs pulse that can be easily used like the vn commodores. Both excellent clear explanations (doubledip-foxdie), makes it a lot easier for us old schoolers. Cheers.

[jezzab]

Any one stepped it up and moved over to 11bit GMLAN instead of 29bit?

29bit is great and you can simulate commands the module is sending but that's it. 11bit you can program the modules via software, request data that's stored in its chips (even the ones that dont have an EEPROM), write config changes (VIN, VIM, options etc etc)

Anyone wanting to have a play I'd suggest reading GMW-3110 2010 edition.. Good read

Just surprised no one is on it? Or posting about it

[foxdie]

Any one stepped it up and moved over to 11bit GMLAN instead of 29bit?

29bit is great and you can simulate commands the module is sending but that's it. 11bit you can program the modules via software, request data that's stored in its chips (even the ones that dont have an EEPROM), write config changes (VIN, VIM, options etc etc)

Anyone wanting to have a play I'd suggest reading GMW-3110 2010 edition.. Good read

Just surprised no one is on it? Or posting about it

It might be because there's a lot~ of information still un-deciphered in the 29-bit realm. I do realise all the juicy bits are in the 11-bit realm, I've taken a look at GMW-3110 (2010 edition) but makes my eyes bleed and brain turn into that of a cabbage

One day I'll get my head around it. Hoping someone else can get there first then explain it to me

Ps. Anyone aware of a document that actually explains what each 29-bit frame is? That'd help us build up the GMLan_Bible so much quicker!