> Basically doing CAN bus diagnostics with an oscope and logic analyzer.

I'm skeptical about this; I can run my 'scope on the CAN bus and decipher the output, but there's no point. I'll use the CAN bus diagnostic reader to determine which of the 27 or so modules are sending malformed messages.

And that, itself, is theoretical - a broken module or poor wiring is still not going to result in messages so fucked up that the diagnostic reader can't read them.

It's like pulling out the 'scope to diagnose your LAN issues; you can do that, but you'd be a moron not to use a network packet sniffer instead.