OBD2 socket install.

[Jas11n]

I wanted to carry on with an original thread where Marty (vagparts) found a socket and loom, but because of recent forum silly goings on I can't as it's in a now defunct section
Thread located here in the now closed Open-topic (Old) forum

Anyway,
It seems to have never been answered in that thread, the fact that's it's not simply "plug n play" It does however have our required four wires and they are in the correct positions on the 16 pin OBD2 socket.
I would really have liked to splice in the wiring coming from the 2x2 connector in the fusebox, but once the parcel shelf was off, I couldn't even see the base of the fuse box for the mass or other wiring, let alone strip, splice in and solder.
I asked a friend who has a complete engine and dash loom from a late 1995 Coupe (also has one from a 1993 Coupe too) and he comfirmed that the K and L lines from the ECU connector to the 2x2 connector don't pass through anything else on the way.
That meant I could tap into the wiring at the ECU end.
ABY ECU and new OBD2 style socket pinout below;

16 pin Socket
Pin 4 = negative (brown)
Pin 7 = "K" line (grey/white)
Pin 15 = "L" line (yellow)
Pin 16 = Positive (red)


Ecu 55 pin socket
Pin 13 = "L" line (white/red)
Pin 14 = negative (brown/red)
Pin 18 = Permanent positive (red/white]
Pin 55 = "K" line (green/red)

Means I can now data log on the go and check for codes all without lifting the bonnet. Works a treat too.















Handheld scanner that stays in glovebox..

[Nuvo]

Nice work Jas, now you can keep an eye on things in the comfort of the cabin.

So is the pictured loom and connector part number 6K0 970 070A as listed in the thread you linked to?

Cheers,
Rob.

[quattronutter]

very handy,which measuring blocks can you access on vagcom?

[Jas11n]

So is the pictured loom and connector part number 6K0 970 070A as listed in the thread you linked to?

Cheers,
Rob.

It is. £13.23 from dealers

very handy,which measuring blocks can you access on vagcom?

I'll link to that info as I'll be here an age..

Linky

Jas..

[A80Avant]

i have done something similar only with the adaptor OBD to the 2 plug that audi uses,and then this ends to a serial plug that goes to my PC/laptop which is old enough to carry one and i have it permanently in the car for this purpose!

[Jamo]

Can't find the original thread Jas11n links to for love nor money, Jas how easy is it to wire into the ecu plug?

[S2central.net]

Jas - don't forget that ALL the K&L wires on the car come thru the A and B terminals on the fusebox - nice easy ringlets that link to the OBD plugs - that is the easiest place to hook em up. I need to post a pic to clarify really.

[S2central.net]

I would personally advice most people to steer away from splicing any new wires into the ECU plug unless they really need to and have the essential skills to do so tidily and reliably... Bad connections there can be a nightmare. Jas has done this the hard way !

[S2central.net]

Two pics attached with a highlight of the relevant area on the fusebox... Those two ring terminals (top left we can call A with the white wire and one below called B with green visible) collect the K & L wires from ECU (and other controllers)... These link to the white OBD plug.

Note the text on the fusebox sticker which clearly shows this - no schematic required.

The two ring terminals are such that we have -

A (top left) is the L-wire
B (below it) is the K-wire

The white OBD plug is wired such that pin 1 (inboard) is L-wire and pin2 is K-wire.

There must be a common point in the loom where all the K & L wires converge as on my car there are only two wires at each terminal - one of those to the OBD plug. I have ECU and ABS that uses OBD so could expect three wires instead of these two... Airbag, immo & climate equipped cars would have extra wires unless there is a sneaky common point somewhere - I don't think its documented on the schematics... All they show is OBD wires going direct to the OBD plug (which aint strictly true).

Oh as an edit - I have just discovered that the above is only true for cars from 05/92. Before that the fusebox layout shows the ring connectors transposed (A=K and B=L). Very odd.

[Jas11n]

Jas how easy is it to wire into the ecu plug?

Piece of cake if you can splice, solder and heat shrink mate.

No need though, the all seeing, all knowing S2central knows better and makes my way a dangerous avenue to take.

Be different at your peril..

[S2central.net]

LOL @ Jas - I know you can splice OK - its everyone else I am worried for !

[Jamo]

Cheers for the info guys, it's on my list so I can have Vag-com in real time with the in-car pc

[Error404]

A nice useful mod as usual Jase, nice one

How come you didn't just use a 2x2 ---> OBD2 adapter from under the parcel shelf?Or have i got my wire crossed and the diagnostics are in teh engine bay on the later ECUs?
I bought one on the cheap as i thought it might be a good idea for when i do my engine swap but I have a 1990 CQ so it has different diagnostics connectors (under the drivers parcel shelf) and i've never tried this 2x2 to OBD2 adapter i bought......

[S2central.net]

The proper 2x2 adapters work great (VAS5051 from memory) but avoid the cheapo chinese/korean replicas - you might be luck, but just as likely to have a duff un.

I had a look at some schematics and they are all over the place with regards pinout on the white OBD connector - looks to be confused by that change on the fusebox in 5/92 - I've heard of some people saying their 2x2 connectors only work when forced the wrong way - which I now presume is cos of this issue.

[Jamo]

A nice useful mod as usual Jase, nice one

How come you didn't just use a 2x2 ---> OBD2 adapter from under the parcel shelf?Or have i got my wire crossed and the diagnostics are in teh engine bay on the later ECUs?
I bought one on the cheap as i thought it might be a good idea for when i do my engine swap but I have a 1990 CQ so it has different diagnostics connectors (under the drivers parcel shelf) and i've never tried this 2x2 to OBD2 adapter i bought......

Only some of the 3B's had it in the car all the rest are in the fuse box certainly ABY's / ADU's