canbus, dashboard, halting communication from another device?

[JPortici]

i want to write stuff on some car's dashboard display.
from my investigation in these cars the display is controlled by a low speed can line from the body ECU, this line not connected to the CANB line on the OBD port
however, there is a mode in which the display writes the info from the radio (frequency, station, cd/mp3/etc) this time available on the CANB line and because i'm lazy and i don't want to remove the covers, cut wire and install a small "filter" unit i just pretend to be the radio sending info.
problem is, the radio transmits its state every 1 second or so (and whenever more info are needed), even when it's powered down, so i can't get a stable image even if i increase the message frequency to the point it's almost saturating the bus (which is bad practice anyway)

i was wondering how to intercept/stop the radio messages without (again) putting myself in the middle and filtering it out

[DBecker]

You seem to be asking if you can jam a specific CAN message.

No, you can't effectively do that.

The sender will keep attempting to retransmit, and you'll saturate the bus trying to repeatedly jam the signal.

Eventually the sender will give up from too many errors, but you risk breaking vital functions before that happens.  And after watching a modest amount of a successful traffic, the sender will reset and attempt to transmit again, repeating the risk to other traffic.

[cat87]

The Dashboard and Radio are most likely on the same CAN bus, so there isn't anything you can do to stop it. If they were on different CAN busses, you might have had a chance by doing some quirky stuff to the car's gateway (hacking, reflashing, etc, but that is hard hard work) so the message does not get routed to its destination.

If I read you query correctly, as an option, what you might want to do, (but this means tapping your own CAN transceiver onto the bus) is send your info to the dashboard. When the message comes from the radio, detect it with your uC and send your info message again, a few milliseconds after the radio status message was sent. That might just force the dashboard into displaying a continuous  image.

I can't really think of any other way to do this right now, but if I do, I'll leave another reply.