OBD1 to OBD2 wiring - Is there a guide anywhere?

[EnthusiastOwned 7]

I'm in the middle of my OBD1 to OBD2 conversion on my 1993 Corrado. I'm at the stage where I have both the Golf and the Corrado wiring looms sat ready to be stripped and I'm a little unsure exactly what needs to be done. The only guide I've found is on the Corrado Forum and it's a little hazy in places. Does anyone know of a more comprehensive guide anywhere?

I am in the thought that I need to match up the OBD2 wiring loom with the OBD1's - Remove anything which isn't used from the OBD2's.

In short, make sure I have the same fusebox end connections and also the same auxiliary end. Anything thing else can be discarded? Correct? Or is there any other extra wiring on the OBD2 loom I need to use?

Any help would be much appreciated

[VR6Pete 1,455]

hi mate, that's the one we used too, and the only sketchy bit I got was the aux pump wiring causing a short, I had a few other issues that made it look like the temp sensor wasn't working, but the gauge had a fault in the end Only thing I can recommend is to run the new loom in, connect everything up so you know what to strip out (I think everyone has their own way of working.....) and keep it to one side, make sure it all runs, no VCDS fault codes etc..... before you wrap the loom up, Im sure I still have a few spare plugs myself, even on my new loom, but before I want to be 100% happy before I chop and wrap them out...

it is a lot easier if you remove the old Corrado loom and you can effectively make a copy, compare them both, unwrap both looms so you know what is what.... masking tape to label the plugs up is also useful

I used Audi loom tape on mine looks great, and has a really OEM feel to the installation now its all tidy.

[EnthusiastOwned 7]

Ahh, ok.

So effectively you're making a copy of the wiring from the OBD1 loom? Nothing else fancy or random connections?

Any idea of the tape part number and how much is needed please?

[VR6Pete 1,455]

That's pretty much it mate, think the only point to note is that you need to chop off the headlight loom off the new OBD2 loom as you retain that from the old corrado loom.... The mistake we made doing my corrado was that we removed the loom that runs down the passenger chassis leg, wasn't any need for that, but we did change the engine harness too that goes to the big multi plug and then the new OBD2 loom plugs straight into it

nothing special to do, the thing to remember is that every loom is different... air-con etc... may need chopping out etc... but once you have it working, and identified the plugs you don't need, it will soon start to look like the old corrado loom again

don't worry when you see you've stripped back half the loom, and have loads of wires and plugs chopped off.... just remember to leave yourself some spare wire in case you need to solder things back together, always worth having some shrink wrap tubes too to make sure any joins are water tight

Just go to any audi dealer and ask for electrical loom cloth tape... my local dealer had 100's of roles in, and cost 3 - 4 a roll.... Think i've had about 10 roles altogether now and have wrapped any visible wiring under the bonnet

[VR6Pete 1,455]

Here are a couple of links you may also find useful

http://www.corrado-club.ca/forum/viewtopic.php?t=5880&highlight=obd2

http://forums.vwvortex.com/showthread.php?3934082-93-Distributor-Corrado-to-OBD2-How-To

Cheers

Pete

[EnthusiastOwned 7]

Thanks for the info Pete. It really helped.

I'm pretty much done with the loom now. It's all in shape, everything is chopped out and any splicing of the OBD1 plugs has been done. I've spent hours tracing and comparing every wire on both looms and it should work first time. The only thing left to do is remove each plug pin and feed the Corrado grommets onto the loom and then fully wrap it all; for that nice OE look

For reference the loom tape has the part number: 000 979 950 and is £5.42 RRP +vat for a roll.

[VR6Pete 1,455]

I've spent hours tracing and comparing every wire on both looms and it should work first time.

Good luck mate Glad the information helped, I didn't bother removing the pins to feed the grommet on, I cheated and sliced the grommet, its still a really good tight fit and still water tight.... Then there is the big rubber thing that looks like something rude that goes over the ECU plug, I sliced and cable tied LOL. you cant see, I just made sure the slit was on the underside as I was limited on time at the time

Cheers for the part number, im sure that would be helpful, I did manage to negotiate a small discount on them as I purchased so many rolls LOL looks great now though. OEM look.