On Apr 11, 3:09*pm, (Scott Dorsey) wrote:
> I believe that the error codes for the other computer subsystems are
> available through the OBD II port, but they are not readable by the
> cheap scanners.

Okay, assume I'm using a PC with OBDII software rather than a
standalone scanner. My assumption is that all codes are of the same
format, whether they are the standard or proprietary codes on OBDII,
so the PC software should be able to at least display the code number
even if it doesn't understand what it's about.

> In addition there are diagnostic modes available on the ports which allow
> you to plug in a scanning device and look at realtime plots of all the
> engine sensor inputs and outputs. *This is an absolute lifesaver and a
> whole lot easier than trying to guess what's happening from an error
> message that says a sensor is out of range, but not what direction it's
> out of range, and with no information about the other sensors that aren't
> out of range.

I believe the real-time sensor plots are available on all cars, it's
not just a BMW feature, right? So it would be a standard OBDII
feature, rather than proprietary.

> The problem is that these cars are computer networks on wheels... there is
> an outrageous amount of automation and a huge number of individual
> communicating systems, and when _anything_ fails you will be completely
> at a loss without information from the responsible system. *The cheap
> scanning tool isn't a bad thing to have, but it's not enough to diagnose
> the vast majority of problems you'll encounter.
>
> Now... the good news is that if it's a 2000 model, it's not anywhere near
> as crazy as a late model BMW. *And if it has a manual transmission, you
> are that much better off because the transmission control system is one
> of the more nightmarish diagnostic headaches. *But this is a car that has
> microprocessors controlling the interior lights... *It's not like the 2002
> any more, sadly....

Yeah, actually my friend wanted a tool that could even tell him if the
windows were opened or closed. Not that he really needs that, but he
does like to be able to have full capabilities. Will these
proprietary, non-critical codes come through the standard under-dash
port?

Yousuf Khan