Originally Posted by jcledfo2
I am having a good ole time trying to figure out these Data Link Connectors for my '94 XJ. I have been having engine issues and want to log what is happening when I run it around the block. I built the simple transistor and double transistor ALDL cable so I can hook it up to my laptop and log with TTS Datamaster or WinALDL. The issue I am running into is that I have searched all over the forums and I am getting mixed answers on the connector I need to use. I have the "L" shaped connector on the driver side beside the ECM. I also have a thin black connector bolted underneath the dash on the driver side (photo attached). Autozone website says this is a DLC too????? There is also a black plug hanging under the dash which is a 4x2 but only has 4 metal contacts in the top row, bottom row is empty. I have tried connecting my cable to the "L" shaped connector but didn't get an signal.
Any help is greatly appreciated
ECM = PCM
It looks like the PO wanted to wear big boy pants and put a DLC under the dash, like the OBD II big boys.
That connector resembles a 1993 DLC but the wire colors don't match the '94 or '93 DLC wires. I've attached a diagram of the '93 DLC as reference.
The '93 and '94 DLC interface match, in terms of wire colors, PCM and TCM termination, and ground and power source.
The PO may have bypassed the DLC in the engine bay and ran his own wires to the new DLC, which I don't think match the original DLC wire colors, and why you can't get anything from the DLC in the engine bay.
You'll have to read out the pin cavities on the new connector to see which is power and which is ground.
Looking at the '93 diagram (which is blurry), the YEL-BLK wire, pin cav 5, goes to pin cav C4 on the TCM connector. The WHT-BLK wire, pin cav 3 goes to pin cav 46 on the PCM - this is the Serial Communications Interface (SCI) Receive Buss (-). The VIO-BRN wire, pin cav 4, goes to goes to pin cav 26 on the PCM - this is the Serial Communications Interface (SCI) Transmit Buss (+).
If you plan on using this DLC you'll need a matching connector.