I am trying to finish up my DIY scan tool and test it out, but I've hit a snag. The pin assignments in the instructions do not match the pins on my ALDL connector. I searched high and low, and even went through all the wiring diagrams, but couldn't get a difinitive answer. I'm using the techedge DIY schematic and diagram for my cable and adapter box.

My car is a 1986 Camaro IROC Z28, engine VIN F. Originally had a 305TPI and a 700R4 auto.

My ALDL connector has 12 pin positions, but only 7 of them are used. The following is what I've been able to determine.

Pin A - ground
Pin B - diagnostic mode select from ECU
Pin C - air select valve (emissions)
Pin D - ?
Pin E - ?
Pin F - converter clutch control
Pin G - fuel pump relay (12 volt powered with key)

I assume that all of these I've listed are correct, but I could be wrong. I'm taking the information from the wiring diagrams given in the tech section.

I need to know which pin is for the data stream. I think it might be pin E, but I'm not sure, and can't seem to get an answer on my own. I don't want to splice into the wiring and have it be wrong, or connect my laptop to the wrong pin and have somehting go wrong and damage my laptop or my car's ECU. Any help would be great. Thanks in advance.

 

Pin "E" is the serial data connector on the ALDL. On the VIN "E" cars there are two connectors, pin "E" & "M" are the serial data connectors on these cars/

 

Thanks Trickster. The diagram I was reading kept calling for pin M, and I'm looking at it going "there is no pin M!" I saw a mention of a pin E, and that's why I figured it was the data pin, but I wanted to be sure. Apparently only the TBI cars used the M pin (VIN E = LO3 = 305TBI). That's also good to know, because I have a TBI truck too, which I could connect up to the scan program.

Thanks again. I'm going to go beat it like Jason Todd.

 

Sorry I forgot to mention this in my previous post. Pin "D" is for the Service Engine Soon light (if used).

 

Just to clarify, the E pin on this car is the 1892 data stream, correct? Since it's a TPI it should be 1892 and not 160, so I would assume that the E pin is for the 1892. I need to make sure to connect it to the right pin out on the scanner board.

 

I couldn't tell you about the 1892 data stream. I can just tell you that pin "E" is the data stream signal to the ECM on the OBD I F-Bodies whether it is carburated, TBI, or TPI and that on the TBI models pin "M" is also used as a data stream source in conjunction with pin "E". Someone else on the board with a little more knowledge of the electronics involved with that scanner board could probably give you more info on that.

 

Okay, I appreciate all you help.