Discovery II diagnostic port reading?

Has anyone had any luck with reading data from a Discovery II diagnostic port using a simple interface such as ELM323/327 and the like?

I've been playing about with the port for a bit today and it seems to be wired for the OBD2/EOBD (4,5,7 & 16) standard but fails the primary 5bps handshake protocol that ELM et al initiate with.

I've been reading all i could find on t'internet regarding it, but it seems to be shrouded in mystery.

There are those who say it's 10k4bps and those who say it's 9k6bps.
Those who say it is OBD2 compliant, and those who say it's nothing of the sort.


Can anyone shed any light on this?

Eh???

Galen said:

Has anyone had any luck with reading data from a Discovery II diagnostic port using a simple interface such as ELM323/327 and the like?
............

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No, 'cause it doesn't work.
Get rovacom/rovacom lite or the new kid on the block: NANOCOM - Land Rover Defender and Discovery diagnostic system

The Nanocom would certainly do the job, but buying something would spoil all the fun of messing with PICs

I might agree with you on the fun part but why would you use an OBD to RS232 interpreter on a non OBD2/EOBD compliant ECU? It's like using a french<>english dictionary to translate some chinese words into english. Where's the fun part here?

cipx2 said:

I might agree with you on the fun part but why would you use an OBD to RS232 interpreter on a non OBD2/EOBD compliant ECU? It's like using a french<>english dictionary to translate some chinese words into english. Where's the fun part here?

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The 323 chip is cheap and the circuit is simple enough to put together, it was worth trying out.

It's alright people simple saying "It's not compliant" or "It is compliant" as in this thread <http://www.landyzone.co.uk/lz/f8/obd-protocols-td5-37896.html?highlight=obd%2A>

It seems that opinions abound on whether it is or is not OBD2/EOBD compliant, yet no one can provide any substantive details of what the used protocol is.

I'm sure we'll find out sooner or later though.

If forums are the places where you got the info from, why didn't you cross checked other forums as well? How about the german, french, italian ones? They have Td5's there as well you know ...

The protocol used is LR proprietary. If you want to decipher it, go ahead. You'll be able to supply an interface and compete rovacom and others. Why not?

You want some proof that the Td5's are not OBD2/EOBD compatible? Ok.

Here's the diagnostic socket schematics:


and the minimum requirements for an OBD/ISO diag socket:



All you need to do is play that "find the X differences between the pictures" game.

I will let you pinpoint what's wrong and why your interface doesn't work. OK?

cipx2 said:

If forums are the places where you got the info from, why didn't you cross checked other forums as well? How about the german, french, italian ones? They have Td5's there as well you know ...

The protocol used is LR proprietary. If you want to decipher it, go ahead. You'll be able to supply an interface and compete rovacom and others. Why not?

You want some proof that the Td5's are not OBD2/EOBD compatible? Ok.

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I've read much more than just forums. I used the link to a thread on here as an illustrative only.

The information you attached shows that the socket and wiring don't support l-line but do support the open collector k-line bus, and that Landrover have augmented the connector by utilising pin 13.

Pin 7 should be present for ISO 9141-2 and ISO 14230 communications; pin 15 may or may not be present for those protocols.

I'll still keep searching for information regarding the protocol used by the k-line bus.

If I ever manage to work out what is going on with the protocol I'll make the information public domain. I'm certainly not going to compete with the manufacturers of analysers.

Keep up the good work and keep us informed...

I looked at one of those bluetooth senders to transmit to a Pocket PC... but the Land Rover protocols stopped me dead in my tracks!

battenberg said:

Keep up the good work and keep us informed...

I looked at one of those bluetooth senders to transmit to a Pocket PC... but the Land Rover protocols stopped me dead in my tracks!

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If you get a working tool, make me one too and I will share the costs.

CharlesY

CharlesY said:

If you get a working tool, make me one too and I will share the costs.

CharlesY

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of course...