1.9 Tdi A4 2003 in Limp Mode

Need some guidance
Have a 1.9 PDTDi 130 Avant Quattro 2003
Had the trouble a while back with wipers but fixed that but disturbed ECU box seal on bulkhead and had some drops of water coming in.
4 weeks ago car went into limp mode
If you knocked off back would reset and go again but would soon go back into limp mode. Then just stayed in limp mode.
Chatted to my mate who owns garage and he said its Vanos vain in turbo.
So I stripped turbo cleaned it up and put back on still in limp mode.
We put on laptop software says P1639
Throttle peddle pulse thing
Now I have read on internet it moistures in wiring not throttle peddle sensor.
I have taken the white and red plug apart under ECU box and sprayed with electrical spray still in limp mode.
Has anyone else here come across this issue.
It’s a proper car low miles more blue it’s a lovely thing so really want to sort it.

Limp mode is triggered by a sensor if I'm not mistaken, always. If you can find out which one you will be able to narrow down your issue, can you look at the values in vcds to check it's all ok? It might be a case of small rewiring or a software fix, as long as it's safe to do so.

Does the throttle stop responding at all? I had a 1.9tdi cordoba and due to where the ECU sat rain water would land on it. I ended up with a lot of grief from the throttle.

Cure was to take the ECU out, clean up contacts and let it dry thoroughly before putting it back together and resealing it.

Might be worth looking into if the ECU has got very wet.