After reading this thread, I decided to give it a go on the wifes 1999 2.5 GLS Auto , as it has had the TC / ABS lights and no speedo for a few months and the MOT was due.
Went to my local breakers and had a look round there Omegas, for the closest match to mine, found a 2.5 manual Saloon on a V plate, they only had a 2.0 auto estate, I thought the this would be the closest match.
The breakers charged me £20 for the ABS control Unit
Managed to strip the only out the donor Omega in about 30 minutes, there was already a few bits missing under the bonnet when I started.
Anyway to cut a long story short, i followed the instructions on here, and fitted the new one, could only get 4 of the 6 screws back in.
Took about a hour to fit in, I topped the power steering fluid back up, and decided to turn the key and see if all my hard work and scratched arms had had been worth it.
started the engine, both lights went out!, took it for a test drive, speedo worked, tested the ABS and TC all working fine, problem solved. I didn't have the car or ABS unit reprogrammed or anything.
Took it for a MOT and it passed!
I did this back in the summer, meant to post my results sooner, but only just got round to it!
I think the problem was caused by oil leaking from Cam covers onto the ABS unit, the electrics had oil on them when I had a look.
Anyway, the Omega died last month, and has now joined its Brothers in the same scrap yard as I got the ABS unit from .
Thanks guys for posting your experiences on here, it gave me the courage to attempt this.
Just got the wife another Omega, a 2.5 Auto CDX on a S plate this time, far better car then the one before