I get this also on my 1.2 and I was putting it down to low voltage as I have an old battery however, now I think about it. It seems to be on cold damp mornings. What is this D4 connector you talk of, any pictures of it?
What I know about it is that it is one of the main wiring connectors. If has the can bus feed and very receptable to moisture and dampness causing corrotion on the connectors. Especially if you have cleaned the engine compartment without the battery cover on. This in turn cause alot of problems with car security, engine fault, abs, asr faults etc in wet weather.
I had a car security fault this winter when we had a snow storm. Couldn't start the car a few times and got fault messages. It disapeared but today i opened the connector and cleaned it out with a clean toothbrush and electric cleaning spray. It had some corrotion on it and I could see that someone has been there before. I will clean it more times in the fall and winter just to be sure.
I thought it was a weak battery when I got the errors but I had driven the car for 2 hours before I got the problem. Was wet, snowy as hell and drove in 40 km/h for 2 hours. I don't think the battery was the problem when I look at it now.
Good one Esaus thanks for that. I will pull is apart and give it a good clean. I did have trouble pulling fuses out to check them so I may have a problem. I also did not bother putting the cover back on so I may just do that over the weekend.