OEM MK4 management wiring => Mk1/2/3 harness install FAQ (Now with added dieselness!)

Will have to check where is that Purple/Red wire located, not sure there is a plug available there on the Big ECU Plug loom but that Seat Toledo VR5 clearly does have one, will go to the scrapyard and check the canister if the plug is there and what actually happened to it.

Hmmm, thanks for the link, will wait and see once i get the VR6 Instrument Cluster and check if the reporting works fine afterwards.

Finally solved !.
Removed the Secondary Air Injection Valve plug from the valve and checked with a testing lamp, there was clearly no power to it.
I did remove the plastic from the 2pin connector on the big ecu plug and there was power to the Blue/Yellow plug, i ran the wires from it to as you said to T14a/13 & T14a/14, checked with the lamp and power came to the other plug and i connected it to the valve again.
Scanned again and the DTC was still there, cleared it and it kept still popping up. decided to chip off the other plug so i can reach it to the valve and ignore the one from the sharan engine harness, while chipping it off, around 10 cm away from the connector the Brown/pink wire was cut so finally found the root cause of the problem.
Wired it, cleared the errors and the error is gone, closed the engine trunk and went for a test drive.... Man this engine pulls, that torque is insane. it keeps getting better and better, it seems that everything does have impacts on performance.
I assume the power will improve even more once i plug the Lambdas into the exhaust so the ECU knows the correct amount of oxygen.
Only DTC left is the Tank Ventilation Valve.

Thanks a lot man, this project wouldn't have been possible without you.
I purchased the engine only after i figured out this website and this beautiful thread and with the only hope that i will manage to do it on my own by getting help from there and i did it !.

 

@rubjonny
I fixed the carbon canister as well, it was that “marked” coolant level sensor wire.
I have named it accidentally when i removed the harness from the toledo.

I am having one last issue hopefully.
That is the AC Compressor power. I kept the old connector but no power is coming from the green/black wire, just to make sure the wire isn’t cut somewhere, i sliced a bit of the wire cover next to the connector from FCM, tested with the lamp but no, i get no power from the green/black wire from FCM.
What could be the cause ?

 

My FCM is part number 357909506A and i have no Black/Red wire, there is power to the Black/Yellow wire only (with just ignition on) and i do have earth into the brown/green wire.

 

This is what i get, i also have the switch connected if it is this one:

 

UPDATE: About the coolant temperature sensor:
A few posts back that i have a picture of a 2 pin sensor on the hose that goes from the thermostat housing to inside (heater) radiator, ( https://www.clubgti.com/forums/inde...-added-dieselness.267196/page-37#post-2511771)
it was on the 2.0L 8V engine and kept that hose since it fitted nicely on the 24v engine as well.
Fortunately i kept its connector/wires untouched but i didn’t know the purpose of it until now.
I was using that sensor for temp gauge on the cluster but after ive seen the error code about coolant temp sensor, i realized what if i connect its 2 pin connector on it (Blue/Red and Brown/Blue wires).
It seems that this coolant temp sensor was used by Climatronic as as soon as i connected it and cleared the codes, that coolant temp sensor code disappeared.
However when i remove the front I will have to check the ones on thermostat housing and their wire colors and see if i can wire temp gauge to one of them as like this now i dont have gauges working, or splice this connector of climatronic and join the gauge wires there as well.

Pressure switch is still there, it comes back, could it be that one for no power on ac comp connector ?.

outside temp sensor: thats for the mfa right, it should have no impact on ac functionality or does it ?

 

I will remove the front later today if i have time or on sunday and id these sensor part numbers and check their connector wires.

About the pressure switch a mechanic friend said that it shows an error since you have no R134a gas right now, that way it also doesn’t switch power to the AC Compressor, is that correct as I didn’t have the pressure switch error before the swap.

The T thread for oil switches is giving me a headache, still haven’t managed to find one, i will fabricate one myself, that’s why I haven’t removed the front yet as i wanted to complete the rest once i do.

About the outside temp sensor i have a 2 pin white connector next to the ac switch, is it su pposed to be that one ?, or it’s something different ?
Is the outside one for ac and the mfa one completely different from each other?

 

Sorry again but i am a bit confused, did you mean:

1. 1H0959625: are you refering to the one attached to the coolant hose as the ac coolant sensor with 2 pin, blue/red and brown blue wires ?

Or 1H0959625 you mean should be attached to the white connector as the ambient temperature sensor (yellow/blue and brown/blue), if this is the case, where do i connect the sensor ?, should it just hang outside to measure outside temperatures, like somewhere on the bumber/grills ?

 

Got this one, since it is on the lower bumper right side near ac pressure switch it should be this one, installed it and error gone:


I think i am done now with figuring out wiring, i just haven’t found the M10x1 threaded T piece yet.
Once i do, i will remove the front and fit the MK3 coolant temp sensor and fit the sensor and start merging/welding wires the right way/shape & isolate them as they used to be.

One question since I couldn’t find this information anywhere else yet, what type of bulbs are the climatronic panel ones ?, picture attached below:

Some are burned so i need to replace them, would prefer led ones but without knowing what type are they, I can’t order them

 

@rubjonny evening mate, having an issue with my conversion, all going to plan, but for unknown reason i have no ignition switch live at spade N. My question is how is Spade N fed? At the moment am using spade G5
Car golf mk1 1990 CE1
Thanks in advance mate.

 

ok that clears things up, mine is 1.8 carb so I decided to have an external fuel pump relay setup. I will hook the trigger to d13? And that way i should have things working correctly right?
Many thanks mate