NefMoto

Hello all,
Because of the helpful recommendations I found on this forum, I was able to use ELM327-based WiFi dongle to connect to various control modules on mk5 VW Jetta. I was able to successfully communicate with the engine, transmission, ABS modules and some others, but couldn't connect to CAN Gateway (presumably, it has an id of 0x19). Every time I sent a channel setup message to 0x19 address, I got nothing back.
In a meantime, other tools like OBDEleven were able to successfully connect to this module. Another related issue is when I tried to figure out which modules this car has by sending channel setup messages is that I got responses from modules it's not supposed to have like AWD (0x22).
I saw somewhere that CAN Gateway is a virtual module, but I'm not sure if there need to be some special extra steps to connect to it. Has anybody experienced anything like this before?

If you have something that does what you want, you could sniff the CAN bus and compare to what you are doing.

That could be an option, I can try to splice into obd extension cable for example, although I'm not very good with hardware.

You can buy 2 or 3:1 OBD splitter cables.

https://m.aliexpress.com/item/32641802308.html?pid=808_0000_0209&spm=a2g0n.search-amp.list.32641802308

Great link, thanks.

I have found some Android app called VAG-UDS which claims to work with Bluetooth ELM327 dongles but doesn't really seem to get any measuring block info. However, it seems to be able to connect to all of the control units I was able to connect to (evident by flashing ABS light when tried to connect it to ABS CU) plus to CAN Gateway. I have recorded a Bluetooth sniff log and it looks like it goes to 0x1F address instead. When I tried to open a diag session with my software and read control unit info, I got:
`1K0907530R  0062BJ533  Gateway   H06 `
Which seems to be a J533 Diagnostic CAN Gateway:
https://www.jimellisvwparts.com/products/Volkswagen-VW/Tiguan/Diagnosis-interface-for-data-bus-gateway-CONTROL-UNIT-AGREED-TERM-J533/5191743/1K0907530AE.html
http://www.volkspage.net/technik/ssp/ssp/SSP_307_d2.pdf
Interestingly, in most of the Control unit descriptions I saw it was supposed to be a satellite tuner. Perhaps in some cars CAN Gateway can be accessible at 0x1F address instead of 0x19.
Let's see if I'm able to get a list of installed control units from the gateway.

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=https://github.com/uholeschak/ediabaslib/blob/master/docs/Deep_OBD_for_BMW_and_VAG.md&ved=2ahUKEwie37qIjfPaAhVKJsAKHVefCEkQFjAAegQIAxAB&usg=AOvVaw0830b4L9CQmnwrX-5eYy_J

In all VW cars the gateway uses address 0x1F.

Very interesting. I'm curious why VCDS/VAG-COM and other apps always display Gateway address as 19. Was it some kind of address convention or just some legacy address nobody bothered to update?

To be honest I have no idea.
For example clusters are referred to as module 17-Instruments, while their TP20 address is 07h and their UDS ID is 714h.

So it looks like control unit number and address list is returned by CAN Gateway module as a response to KWP request with an SID of 1A and 9F parameter. So CAN Gateway has a number 19 and address of 1F in that list. Why module numbers and addresses are not equal, I'm not sure, some VAG legacy thing, perhaps.