OTC is a brand of scanner that is either 100% GM or 99% GM. It'* kinda old school and not th ebest scanner, but with my OBD1 scanning experience it'* the best of the few ones we have at the shop [Snap-on, and one other i can't think of the name... but it sucks bad]. Just go to a GM dealer, say you need a scanner, then ask if they have an OTC 4000 scanner or equivalent OTC-brand scanner for your car.

The GM tool was the TECH 1. The OTC 2000 had cartridges and special cables for GM, Ford, Chrysler, and some imports and only did OBD 1. It was replaced by the OTC 4000 which can do OBD i and II but generally is considerably more expensive than a 2000

I believe the last cartrige for the 2000 was the 1994 "3 in 1" aka "Pathfinder".

If considering a 2000, make sure it has the GM two row cable and GM cartridge at least of the same year as your car (the 1989 cartride does seem to work for a 1990 Bonneville)

Thanks for all the input.

I went to the shop yesterday and they read the codes with a tech 2 reader. The problem is a part, that I don't the english name for it ("modulator"), but if I where to transleate the swedish word for it it would be like "module that do stuff". The "thing" is apperently attached to hydralic brake pipes if that'* a clue...

Anyway, now I am told this thing costs about $2800 - twice for what I paid for the car. The shop told they could source a used one, and mounted on the car it would cost $1400...

So, because this is just not in my budget, my plan is to disable the abs-light instead so I can get the car trough yearly inspection.