Obdll not powering up

Hi Ernie,

Assuming the scan tool is not the issue, you need to have power and ground to both the module and the DLC for it to communicate. Here is wiring diagram for the DLC. I would check the grounds and then check for power on the B+ circuit DLC.

Use a volt meter set on ohms and put the red lead on the ground pins of the DLC and then put the black lead of the meter on a known good vehicle ground, preferably the negative battery post. You should have less than half an ohm. If either are open or high resistance, then you need to repair that connection.

Then switch to volts, and measure your voltage on the B+ wire at the DLC. Red lead on the pin of the DLC and then black on ground. You should have battery voltage with the key on.

If you are not able to communicate with any module because the tool doesn't power on when connected, then most likely the DLC power and ground is your issue. However, if you just can't communicate with a single module, then that module is most likely your issue. Either power/ground to it or the module itself has failed.

Let me know if this makes sense and we can go from there. Thanks