[Shop-talk] OBD/can/whatever scan issue.

[Randall]

---- Doug Braun <doug at dougbraun.com> wrote: 
> Fairly new cars use the "CAN" protocol, and older scanners might not
> support it.
> But the CAN protocol has been common for at least 7 years.

Actually required by law in the US, since 1996 model year.  But CAN is only a physical and data link layer, similar in concept to 10Base-T and Ethernet.  There are lots of layers that run on top of it (think TCP/IP and HTML) as well as lots of possible variations at each level.

For example, my 95 Buick uses a CAN bus, but practically none of the scanners support it because it is still OBD-I and uses different (GM proprietary) addresses and message types than specified in OBD-II.

My understanding is that OBD-II was supplanted in 2008 with a newer protocol, called ISO 15765-4.  But I've not had to dig into it yet.

Randall