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Sniffing GMLAN CAN BUS - possible?

PostPosted: Mon Oct 15, 2012 4:41 am
by foxdie
Hi all, hoping this thread is in the correct place.

I have an OpenPort 2.0 adapter and a Vauxhall VXR8 (which is simply a rebadged HSV Clubsport E1), I'd like to start sniffing its CANBUS (which I believe is known as GMLAN, 29-bit packets), in particular the slow bus (that deals with steering wheel controls etc).

Is it possible to do this with my OP 2.0 somehow?

Many thanks in advance :)

Re: Sniffing GMLAN CAN BUS - possible?

PostPosted: Mon Oct 15, 2012 1:51 pm
by foxdie
Okay, just to add to this, I found and built canlogger.cpp, had to make a small tweak to get it to build in Code::Blocks;

#include <time.h>
#include <cstdio>

#include "..\common\J2534.h"


It logs data (although whether it's garbage or not I'm not sure yet), but given the rate at which it generated a 2MB log file (<30 secs) I'd say it's quite happily logging the high speed bus, I'm after the low one :)

I'll keep poking around, but if anyone knows an easy way to modify the source to log the low speed bus and can let me know, that'd be fantastic.

Kind regards,
J

Re: Sniffing GMLAN CAN BUS - possible?

PostPosted: Wed Dec 12, 2012 8:55 am
by foxdie
I'm going to assume this is dead, I approached this (sadly) without my OP 2.0, details here; http://is.gd/mbedgmlan

For anyone else looking into this, I found out more information, GMLAN runs via pin 1 on most GM / Vauxhall cars but isn't always exposed directly (usually the BCM ECU sits in the way and "bridges"), but if you're lucky you'll find the network sat there is a single-wire CAN Bus operating at 33.33kbit :)

If someone knows how to fudge the OP 2.0 to access a single wire CAN on pin 1 at 33.33kbit, I think it'd be quite handy to a few others :)

Re: Sniffing GMLAN CAN BUS - possible?

PostPosted: Tue Jul 30, 2013 9:37 pm
by ljtorana
Hey man,
Bit late in this but wondering if you actually got into the GM ECU?
(I'm in Australia - it would help a few here!)