Can someone give the link to OBD standard please ...

If you can read german this might help you:
http://www.obd-2.de/

Everything I ever needed was there....

elmelectronics have a cheap odb-2 to rs323 chip and some docs:
http://www.elmelectronics.com/Misc/OBDInfo.htm

and there is a scan tool at:
http://freediag.sourceforge.net/


This should be more than enough to get you started.

Actually it's quite easy.

Now if the empeg guys could finally finish that visual-plugin-interface

Thanks ...

Ist there somebody out there who is still interested in OBD-2 and Empeg? As i'm aware Philb has started programming a bit for the Empeg. Maybe just the release of the first code snipplets could give the project a chance.

And for everyone who doesn't know what ODB-2 is:
IIRC the ODB-2-standard is a must in every car since 1995, so I could imaginge that even your car is capable of such a system. This is a bus for diagnistic purposes where some control units (motor, abs, airbag uses different units) are connected like in an ethernet. I don't know much about ODB-2 but I own such a (bought) ODB-2-converter to connect a notebook to a car's ODB-2-Plug. You can build this converter on your own, it should be less expensive than, say, $30, maybe less than $15...

Rolf

One step further:

There is a chip calles ELM323 which communicates on the empeg-side with AT commands so it should be easy readable.

The chip (PDF):
http://www.elmelectronics.com/DSheets/ELM323DS.pdf

Rolf

Definitely interested!!

For those that want to know a little more about OBD, read this post at MP3Car.

I would be, but I can't do C well enough. Espically since my little converter board for the VFD is RIGHT NEXT to my car's ODB port.

Mer.

I didn't program the empeg until now but I'm sure it will work to get information from the serial port. But there's another problem: the serial is used by GPSapp, I need five or six more ports for all the things I'd like to do. Maybe a manual switch would work. Then, quite important for me, I have to check if this chip (the 323) will work with my Corrado VR6, but I'm quite sure it will. My next steps are:
1. Build this circuit board with the 323 chip and test it with windows.

2. Get information about howto get/put information from/to the serial port of the empeg, maybe it's more tricky than with Linux at a normal PC.

3. Hope I'm not alone here because I have to learn programming the empeg from the scratch...

Rolf

In reply to:

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3. Hope I'm not alone here because I have to learn programming the empeg from the scratch...

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Don't think otf it as programming the EMPEG. You're simply making a C program under Linux. If you have a space PC, load a Linux distro on it (I use RH, because it's what I have at work.. Many, many systems with that on it..) program in it, run it on that, and then when you want to test on the Empeg, just re-compile under the toolchain, and FTP it over.

Me.

Is it that easy? Wow. I'm programming under Unix/Linux for years, so this should be no problem, so I will get the package and compile it on the empeg.

Rolf

:-(

Obviously my car uses the KWP-1281 protocol, so the ELM323 won't work. I have to find another chip, if exists, first.

Rolf

Is there a list of car makes/models and the protocols used?

I honestly didn't know there WAS more than 'one' protocol..

Me.

I remember there being three differant OBD standards, plus CAN-BUS. But it is 8 years since I worked in Automotive diagnostics, so there may be some new ones now too, plus all of the old manufacturer specific ones from before OBD was 'standardised'

The good thing about standards is there are so many to choose from!

EDIT: This was taken from the website of the company I used to work for "ECU Serial Diagnostics - ECU communications to industry standard protocols such as KW2000, KW81, KW82, Class II, or DS2 via CAN bus or ISO-9141 variants. Other application-specific protocols can be implemented on a per-project basis", so it looks like the industry is still far from having one universal standard.

On newer cars at the diagnostic port (under driverside dash) there are only 3 standards: Ford, GM and iso (foriegn and maybe chrysler). There are ELM chips available for all 3 protocols. From any of these 3 protocols you should be able to intercept a lot of information from the car's onboard computers. The other protocols are proprietary and added in addition to the 3 standard protocols. On older cars I don't think there was a set standard (other than OBD-1).

(I mean foreign "to me" as imported into the US)

Hmm... So would it be possible to make ONE 'conversion board' and then inter-swap an IC or something to make it work on all three (four?) protocols? That'd save a lot of overhead hassle..

Me.

I don't know if the driver chips from ELM that do the three variants of OBDII are pin compatible, so just swapping one out and in is probably unlikely, you could do one board with three sockets, and just populate the one you wanted to use.

I am pretty sure that CAN-bus would need its own driver IC, as from what I remember it is pretty differant to OBDII in terms of both electrical signals and protocol.

If I was doing a project to support them I would get a microcontroller, and write the SW for it to handle all three of the OBDII protocols in one device, but I already have a backlog of projects that are not getting enough of my time as it is

I'd like to get started playing with OBDII and see if my car (2002 Maxima) will report anything useful. But I still have a couple of questions.

1) according to obdii.com :

J1850 VPW--The connector should have metallic contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2--The connector should have metallic contacts in pins 4, 5, 7, 15, and 16.
J1850 PWM--The connector should have metallic contacts in pins 2, 4, 5, 10, and 16.

But my car's connector has pins: 1, 4, 5, 7, 8, 9, 12, 13, 16. Do I have a mutilated ISO since I'm missing pin 15? (It's also only one pin shy of J1850 VPW) The top of that page says:

Pin 15 - ISO 9141-2 L Line

Sounds important, is it?

Edit: Nevermind, I just found this comment that says it's OK to be missing pin 15.

2) The ELM323 looks like it's just the chip. Is the a recomendation on a complete cable assembly that I can just plug one end into the OBDII port and the other into the empeg?

I don't have any OBD experience, but I like puzzles. I'd like to see how much info I can get with freediag and go from there.

The ELM323 looks like it's just the chip. Is the a recomendation on a complete cable assembly that I can just plug one end into the OBDII port and the other into the empeg?


I don't know if you're still lokking for a complete cable but www.scantool.net has complete assemblies using the Elm chips.