i have a 1990 760 turbo wagon , it wont self diagnose on the engine side of the self diagnostics socket the manual im using says that terminal #3 is for testing and diagnosis of the ignition but when i insert the pigtail in the socket it does nothing no codes, no testing nothing , but when i put the pigtale in #6 it does do all the testing for the transmision side of the unit. the car is at no start no spark now and ive checked the crankshaft sensor and it works . can anyone help or has anybody experienced this before

 

The book you have must be wrong.A1=transmission A2=fuel system A3=ABS A6=ignition

Do you have fuel?
Do you have injector pulse?