Hi all - long time no speak. Hope everyone had a good Xmas and new year :-)

Anyway, to the problem:

I have a friend who has a Renault Scenic 2004 model, and it's misbehaving
rather badly. On operation of certain controls (e.g. indicators, lights,
etc) the dashboard displays go crazy and occasionally the car completely
shuts down until the battery is disconnected and reconnected.
I had a quick look today and my guess is it's probably a bad contact on the
battery positive or earth (I wiggled the positive terminal lead and got the
fault to come and go. So we took all the contacts off and I have cleaned
them up ready for refitting everything tomorrow. Hopefully this and a check
of the earth points will be all that is needed...

BUT

In case the above doesn't solve things, and out of the desire to both help
out and expand my electronic knowledge into automotive protocol territory,
I thought about hacking into the ODB-II bus and checking for error codes.
>From a quick Google, what I understand, it being a european car (we're in
the UK) the EODB standard is ISO9141-2 (according to the WIki page -
http://en.wikipedia.org/wiki/On-board_diagnostics#EOBD)
It seems the protocol is like UART but one line bi-directional, with speeds
of 10.4kbps IIRC. So I (think I) have a good idea where to start (i.e. bit
banging with a PIC18 or 24 and using some simple transistor level
translators or a MAX232) but if anyone has experience in this area, advice
or even some ready written routines, a decent schematic (some of the ones I
found on the 'net were terrible) or any useful info/datasheets on the
protocol to speed things up it would be most appreciated.
Ideally I'd like to hack something together and try it out tonight, as my
friend is pretty stuck without his car and doesn't have the funds to take
it to a Renault dealer (also past experience with the local one suggests
they will be pretty useless and expensive)

Thanks for reading,
Oli

--=20



Oli Glaser

Technical Development

Irwell Springs Ltd

oli.glaser@irwellsprings.com



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