I must be missing something I have a homemade code reader for the W124 E320's but the pin connections on the 400E are alot smaller and my bananna plugs won't even start to fit in the holes. The part number from radio shack are the same for my code reader on the e320's and the attachment you sent me on the W140 chassis. I know on the E320's you only read codes on two of the pins. How do you do it on the 400E? Do you just read certain pins or all pins.