Hello!
I've got the problem with my '93 PA - ABS and 'traction off' lamps stay on after I start the engine - at the beginning they went off after some distance but only if I turned off the engine and started it again now they stay on all the time. Any idea?

You need to scan this with an abs function scanner for codes, most likely a wheel speed sensor is the culprit.

How can I do that?

How can I scan ABS system?

with an abs function scanner
The answer to your question was posted above.:iceslolan You may need to take it to a shop & have it scanned to get the codes. Midas, Just Brakes and some other brake shops, keep an ABS scanner on site.