I got the 2005 mk2b model without the relays and I had the same problem when I got the car. I managed to find a used one on ebay (with Virgin ECU *SO THEY SAID*) fitted it the day it came, still had same problem. So I sent it back, got my money back an thought not to use eBay again for parts unless they’re brand new.
DONT GET A USED ONE FROM EBAY
I got mine from a site called ECU TESTING. If you wanna have a lifetime guarantee then you have to send your old unit to them when you’ve received the new unit.
I got mine from here in the end^^
ABSOLUTE TOP NOTCH SERVICE
The one I got from that website has been in my car for the past year and half, haven’t had any problems with it at all. Tbh I completely forgot I even had this problem to begin with but with the help of ECU TESTING I had it all sorted the same day I received my new unit.
Any questions you have on fitting it just reply with the question and I’ll get back to you asap
*EDIT* I forgot to mention, make sure you match the new ECU code with the old one to make sure you don’t run into anymore problems down the road.
For example: my old unit had 1077 written on the ECU so I made sure that the new one I bought had the same 1077 code written on there