Pinouts for the diagnostic port on A1992 MMW E30 318I?

You might be able to pull codes using the CEL, but you can only get engine related codes and cannot erase them without a scan tool. This is only possible if you have the newer ECU in your car though. You need to look on the Motronic box and see what the last three digits in the part number are. If it is 173 the stomp test should work. The earlier 153 won't.
For the stomp test you turn the key to on, then step on the throttle 5 times in a rapid manner, less than one second apart. The ECU should then start flashing the CEL and you decode it by counting the flashes. There will be 4 digits, If you see a flash then pause that is 1, flash, flash, flash pause = 3 and so on. It will flash the 4 digits, then move to the next code. If there is only one code it will flash it again. You cannot read or reset air bag codes without the proper scan tool though. Those are a continuous code as well, if the SRS light is on there is a problem. It would reset itself once the problem is repaired but without a scan tool locating it would be difficult. You cannot jumper the pins on them as they do not use a protocol that allows that. Instead the scan tool simply pulls the active data stream and decodes it to get live data and core information. Jumping the pins on that vintage will only damage the computer.