Finally built one of those readers with parts from radio shack. Before I start plugging stuff in (and possibly damaging expensive computer modules) I thought I would ask for help with how to use it. If I understand everything correctly, the black lead is plugged into pin #1 and the yellow lead is plugged into pin #6, #7, #10, or #14 depending on what codes you want to read. What is the difference between pin #3 and pin #16 and which one do I plug the red lead into. Also, what does HFM/SFI stand for and what does EA stand for? I have the 16 pin connector block on my 94 e320.

Thanks in advance.

J. M. van Swaay

Pin 3 is the 12v power on the 38 pin connector, not the 16 pin. On the 16 pin connector, which you have on the 94 E320, the red plug goes into socket 16. The most important sockets are 8 and 14, and of course the built in LED light. HFM is short for hot film mass air flow sensor. SFI is sequential fuel injection. EA is electronic accelerator. You're not going to hurt anything.

All your questions for pin specs and code chart have already been answered in a post inquiry of yours last month
1994 E320 fault code 35 and 84