Custom CDC to SID text

Posted by Karlis on Dec 27, 2015; 12:44am
URL: http://bluesaab-forum.90.s1.nabble.com/Custom-CDC-to-SID-text-tp90.html

I wonder if anyone has been able to crack this yet... :)

The basic thing is that it seems CD changer doesn't send any text directly to SID. Instead it "reports" its status to IHU, which in turn then sends the text to SID. For example "CD1 PLAY MM:SS".

So far I've tried "blasting" the custom text via 0x328 (SID audio text) but that causes the text on the SID to flicker alternating from the "original" message to the one I was sending on power on and on any button related action. I've seen people on the web sending custom text via 0x337 (SPA to SID text). That I believe works fine but I'm not quite sure how it would behave on cars with the actual SPA installed.

Could we intercept the original 0x328 message somehow and tell SID to ignore it and take our custom one with a higher priority? Some sort of software "man in the middle" attack, without the need of splicing the wires.

Any ideas are welcomed. :)