Diagnostics on an ABY in type 85

[HenryG40]

Morning,

I have a type 85 quattro that's been converted prior to my ownership. I've tried connecting a diagnostics cable and have had no joy so I just wanted to check how the wiring is supposed to be.

The two connectors should have two wires:

Connector 1
Blue - "K"
Yellow - "L"

Connector 2
Red - 12V
Black/Brown - Ground

I guess the 12v and ground can come from anywhere but it is the K & L I wanted to check. From pin 13/55 on the ECU connector is the White/red wire for the "L" and from pin 55/55 with Green/Red wire for the "K" line.

This is what I have at the moment:


So I think I need to run the 4th wire from the ECU
Thanks

[UrS4boy]

Diagnostic Plug info including ECU and Fuse wiring

Here is some info that might (or might not) help (have a look at all of them, especially the last one)

ABY/ADU K and L wiring (ECU pins 13 and 55, as expected):



And RS2 fuse box (blue connector is not used)



For the RS2 (and ABY) fuses, the diagnostic power is from Fuse S21:



General Diagnostic plug wiring (wire colours are wrong):



And example (AAN) of K and L connections to an ECU showing the K/L T55/13 and T55/55 connections for the one connector and then fused power and a ground for the other connector, i.e. no additional connections to the ECU. You need the K/L T55/13 and /55 connections to the one plug and power from Fuse S21 and a ground wire in the other.



Diagnostic Plug info: http://forums.quattroworld.com/s4s6/msgs/90409.phtml

[HenryG40]

That's great, thanks.

I will get the multimeter out and check the ground and 12v supply, then look into running fresh K & L wires. I guess there's no reason why I couldn't re-locate the connectors into the glove box

[UrS4boy]

I will get the multimeter out and check the ground and 12v supply, then look into running fresh K & L wires. I guess there's no reason why I couldn't re-locate the connectors into the glove box

If your wire colours running to the white diagnostic plug are as you stated in your first post, they are correct:

I guess the 12v and ground can come from anywhere but it is the K & L I wanted to check. From pin 13/55 on the ECU connector is the White/red wire for the "L" and from pin 55/55 with Green/Red wire for the "K" line.

No need to run more wires for K and L, other than making sure that they are in the correct positions in the white diagnostic plug. The you just need to have a red wire from the downstream side of the S21 fuse going to the correct location in the black plug and the ground to the other one.

[Error404]

The ECU ring terminals are probably not connected to your diagnostics connectors unless the person that did the swap also fitted the ABY fuse board, as older fuse boards don't have the terminal post for the ring terminals to mount. Have a look under the dash for a loose ring terminal on (iirc) red/white and green/red wire. That is your k-line & L-line

HTH

[HenryG40]

That's really useful to know, I'll have a good look and see what the situation is this weekend. It's frustrating not being able to check fault codes!

Cheers