hey i have a 95 z34 and for the heart of me i can not get it to give me any diagnostic codes, weve tried a junky $20 reader, no go, we bought a nicer one, still nothing, i asked a guy i know at the parts store to let me borrow his very expensive profesional reader, i got nothing, weve checked all the wires to make sure theyre connected, common sense right, but we found no loose wires and no wires missing, when i bought the car it was obvious the previous owner had attempted to put in a new remote start and unlock. im just wondering if we missed something and why i cant get anything on a reader.

Chances are that the '95 had the 12-pin (older style) ALDL connector. However, the PCM does not use the older style diagnostic request protocol and does not display error codes via the MIL or "Check Engine" lamp. In order to access the PCM data, you will need a GM Tech-II, Snap-On MT-2500, MATCO Determinator, or similar fully functional, bi-directional communicating scanner. The system is not completely OBD-II compatible, so a strictly OBD-II scanner will not work, no matter how much it costs.

There should be contacts in the ALDL in positions A, B, H, and M.

alright ill give that a go, the help is much apreciated.

yeah, the pcm connection is the older style. i know this from experience :)