959Lover

Can anyone snap a picture of what the OBD port looks like on these cars? AFAIK, they are round with 4 pins or something. Should be the same in later 944's, 951's, and 968's. I have NO idea where the plug is tucked.

MAGK944

On plate in the LH engine bay area, above the wheel well and near the firewall, adjacent to the fuse box and next to all the emissions valves/switches which you can see in the picture. Normally covered by a cap, just look for a black circular cover in that area.



M

959Lover

sweet! Just what I needed, thanks a bunch.

jtsporsche

question, what is it?

Mamooguy

Diagnostics port, I believe.

Calmchaos

Yerp, diagnostics.
Why do you ask 959lover?

And mine only has 3 pins.

FRporscheman

968 has a differnt plug and location - I don't know what it looks like because I've never uncapped it, but it's located under the glovebox.

959lover, you have an exquisite avatar sir.

jtsporsche

like when somethings wrong with the engine and you plug the little computer in to see whats wrong???

Calmchaos

Im not sure... theedge would know.
All I know is it is "on board diagnostics", and when I was making my wiring harness one of the wires shared a pin with the TPS. And I think the other wires went to the ground and the temp sensor.

MAGK944

ISV is wired through there also

959Lover

Why thank you FRPorscheman! You do as well? May I ask, is that your 968? That is a fine photograph! Where was it taken?

959Lover

Yes

Ahso...

I am asking because I would like to possibly make a low cost version for the Porsche community. I have NO experience whatsoever doing such a thing, but it will help me contribute to a community in which I have some interest in joining in my following years. Also because it's just silly that I can buy the OBD cable for my car for around ten bucks but you guys have to dish out hundreds. Kill two birds with one stone, yes?

Also, do you mind taking a picture of your 3 pin connector? I'm interested to know if the layout is the same and just one pin is missing or if the arrangement is completely different.

959Lover

And from my knowledge of VAG systems, there should be some signal from the Oxygen sensor, or at least something straight from the ECU to be able to have on the fly data, as well as the ability to affect the car's systems (turn off airbag light, etc).

Calmchaos

same arrangement just two pins missing.
The ones at 6 and 12 o clock in that picture are not in my connector.

But since I just made my own harness. I deleted that plug and left the wires.

Zero10

There is a data out pin there, but to issue commands to the ECU you actually need to solder a connection inside the ECU (IIRC). I looked into this for a while, using a PIC with a line level converter to actually send/receive the data, if I used a 16F4550 it would have USB HID capability and it wouldn't be that hideous to tie to to a computer, however in the end the work of adding a connection inside the ECU proved prohibitive.

The other alternative is to re-program the EEPROM in the ECU to automatically just dump data to that pin, which is good in one way, but I have no idea if anything bad will happen. A couple years ago I raised this issue here on Rennlist and over on Pelican and one guy gave me some of the initialization codes to issue to the ECU but then everybody went dead and couldn't provide any more information. My project never got off the ground. Sure wish I had one now, troubleshooting a really stupid irritating stumbling/running rich issue