E32 735 IA from 1990 tester connection problem

[gabrielbecheanu]

Hi
I need technical informations
I own a 735 made in 1990 september whit EML and ASC+T and i have a big problem. Until now i try to connect my car to a varios bmw testers (BOSCH KTS Original BMW tester and Carsoft 6.1) and it is imposible to connect whit my car.
I check all the cable from the motronic to the 20 pin connector. All the cable are ok. I don`t know what is the problem i try to use another motronic unit and the result is the same no connection (the car works 100%) all the systems are ok only the connection is the problem it is only one think theat i not change the OBD i look at dthe wiring diagram and i see theat the cable theat goes to 20 pin conectors goes also to the OBD.
Please help me to fix this problem.