OBD2 wiring question

[easypops 8]

Good evening, I’ve read the threads covering this so many times I should be able to figure this out, but as I have no way of testing this, I’d appreciate anyone that can give me some help.

Ive got my OBD2 loom all wrapped and ready to fit. I stripped it side by side with the corrado one, removed all the stuff that was to be gone.

 

There is only one thing I can’t answer, Pin G/3 on my golf vr6 loom has a short black wire that does nothing. On the corrado loom, pin G/3 corresponds to pin 6 on the ecu plug-Fuel pump relay turn on. The golf loom has the same colour of wire at pin 6 yellow/blue, but on the golf loom it ends in a plug. Logic says remove the black and replace with the yellow/blue pin 6 to G/3?

But I read this from the very guide on here, which basically kills that idea.

So, any of you clever people fancy solving this for me ? 😁

Oh, and I remover the golf loom myself and I didn’t cut said black wire in G/3

[tonedef 8]

Did you get any further with this? I've had a look this morning (mirror on a stick and head torch!) and the wire coming out of G1/3 on mine is black too but it disappears up into the loom behind the fuse box and I lose it. I've checked all my notes and drawing mark ups from the OBD2 installation and I've made no comment there, I even highlighted the yellow blue wire at the time to mark that I've installed it, and all the drawings I have show it going from G1/3 at the fuse box to T68/6 at the ECU via connector T2b behind the fuse box, no mention of any black wire. I did mine in 2011 so my memories of it are a little hazy though.

I can drop the parcel shelf and pull the fuse box out for a better look later on if you haven't found anything, I haven't had it out of the car for whole weeks now! I'm sure there's a simple answer in there.

[easypops 8]

39 minutes ago, tonedef said:

Did you get any further with this? I've had a look this morning (mirror on a stick and head torch!) and the wire coming out of G1/3 on mine is black too but it disappears up into the loom behind the fuse box and I lose it. I've checked all my notes and drawing mark ups from the OBD2 installation and I've made no comment there, I even highlighted the yellow blue wire at the time to mark that I've installed it, and all the drawings I have show it going from G1/3 at the fuse box to T68/6 at the ECU via connector T2b behind the fuse box, no mention of any black wire. I did mine in 2011 so my memories of it are a little hazy though.

I can drop the parcel shelf and pull the fuse box out for a better look later on if you haven't found anything, I haven't had it out of the car for whole weeks now! I'm sure there's a simple answer in there.

If you could be arsed doing that mate, I’d be delighted. I’d love to know where to put the yellow/blue and to where the black G1/3 actually goes. 
The yellow/blue wire with the black plug in my picture 100% goes to pin 6 on the ecu plug

[tonedef 8]

Sorry, bum steer there! That must have been a new record for me getting the fuse box out and back in again as well as opening the ECU plug to check the wiring just to find that I was mistaken earlier and when I'm not laid in the footwell looking in a mirror the wire in G1/3 turns out to be Yellow/Blue and goes directly to T68/6 at the ECU. The black wire is in G1/4 and that goes to the coil pack on the wiring diagram.See photo for confirmation.

All goes to confirm that the wire you're looking at from the ECU should be connected there, I don't suppose the donor Golf had an immobiliser fitted that was wired into the fuel pump?

[easypops 8]

Thanks Tony,

That is exactly what I was hoping to see. I really can’t remember as I took the loom out the golf way back when you did your swap. I bought the golf as a non runner as I only wanted it for the OBD2 and Teves20 stuff. I know I didn’t cut that black wire but an immobiliser would make sense.

Anyway, I’ve now put it where yours is 👍😁

 

[tonedef 8]

No problem Martin, glad to be able to help, lets hope it does the job now. There must have been another issue in the post you put up last night from Serial that was keeping the ECU from switching the fuel pump.

[easypops 8]

7 minutes ago, tonedef said:

No problem Martin, glad to be able to help, lets hope it does the job now. There must have been another issue in the post you put up last night from Serial that was keeping the ECU from switching the fuel pump.

Hopefully mate, I actually messaged him about it a while ago, however he said he couldn’t remember how he sorted it but assured me it’s a worthwhile upgrade.

Thanks for your help(again) 👍😁

[fla 9]

Martin? Yours doesn't have aircon does it? I seem to remember having an issue with mine working out the signal wiring which went through a red connector. 

I'll check my notes again although i also used notes from Tony.

[easypops 8]

1 hour ago, fla said:

Martin? Yours doesn't have aircon does it? I seem to remember having an issue with mine working out the signal wiring which went through a red connector. 

I'll check my notes again although i also used notes from Tony.

The golf VR6 that I robbed the stuff from did indeed have air con. Happy to hear anything you have mate 👍😁

[fla 9]

6 hours ago, easypops said:

The golf VR6 that I robbed the stuff from did indeed have air con. Happy to hear anything you have mate 👍😁

Hope these are of help

Aircon wiring diagram diavia.pdf T42 connector pinouts.pdf T42 connector pinouts.xlsx

[tonedef 8]

I'd forgotten about that unexpected benefit of the OBD2 wiring that allowed me to remove the Passat overlay loom and simplify the Climatronic wiring, maybe you could do that while you're in there 😗

[fla 9]

I removed all the redundant wires from the obd2 loom but wish I'd left a few as 'spares' - saves adding new ones which i need now. Just a thought before you wrap everything up

[easypops 8]

Thanks guys, I’ve already wrapped the loom and it’s good to go, late addition of a wire for the vdo gauges. No Climatronic for me,,not after the effort required to refurbish the original heater controls/matrix etc, it’ll hardly get used anyway 😁