Ok. The battery is now fully charged. I connected the ABS unit again just to test. Still running. Now, there's no point in doing a scan with the ABS unit disconnected because it's gonna throw all kinds of codes and I don't know what's what. Should I leave the charger on and connect the ABS unit and do a scan? If I pull the fuses, isn't that the same as disconnecting the unit?

And just to be sure, there's no external relay dedicated to the ABS unit? If all these things are fine(fuses, relay), then it's leaning towards the ABS module no?

EDIT: Just opened the driver side fuse box and it's all wet. All the fuses seem fine when I check with a multimeter but that can't be good. Coming from the upside and been running down over the fuses and inside the contacts on some

Don't know if you see much here:

https://i.imgur.com/CwC6rkG.jpg

Should I replace them all and blowdry the panel or something?

Oh no! I would disconnect the battery and see if you can take that fuse panel off completely. I would then try and clean all the contacts with IPA as that would help rust preventing. Obviously get to the root of the leak too+++

Check the plenum chamber for water too. My 2003 D3 had a water ingress problem that caused all manner of weird things to happen and was absolutely solid once it was cleared up.

I dried out the fuse box, sprayed som electronic spray on there, replaced all the fuses and even the J329 relay which feeds the ABS unit and a bunch of other things. It's the terminal 15 relay. Pump is still running. Maybe there's a short circuit in the module or something.

It has fixed a bunch of other things though. Like the steering wheel adjustment when you turn on/off the ignition, the child lock for the rear windows etc. But I need to find the source of the leak. Are there any drain holes around there that could be clogged?

My friend is currently repairing the ABS module. I'll let you know if it fixes the problem

Well, the repair didn't work, it still runs. It did have some damage though. Maybe the only way is to get a used working one and try. Thing is, I can't find one for a decent price. Anyone?

These are the numbers tha are on the unit:

4E0 910 517 A
4E0 614 517 E

Doing a second attempt with the repair. Thinking it might be the transistors so gonna switch them out

My engine coolant reservoir has a small split in it and when the system became pressurised it caused it to leak.

It eventually trickled down on the ABS module and caused all manner of problems..

Might not be this but no harm in checking.

In the end I replaced the module and had it coded and never had a problem since.

That's not impossible. I just replaced the coolant reservoir because the fitting on the reservoir where you put the hose on was broken in half so one piece was stuck in the hose and then they had just glued it together on the reservoir again. It was for the upper hose that runs to the back of the engine.

The ABS module didn't seem wet though. If this doesn't work then I'll have to get a new/used one.

it's not usually the ABS block that causes the issue is the actual electric module that causes problems.

you can replace just the ECM if I remember correctly. However, if you're buying this used, they often come attached and sold as 'one'.

You'll need someone quite handy to code it all in once you're done.