You need to check continuity and for dead shorts on the two wires that connect the PCM directly to the OBD port
There are two signal wires for the BUS system a + and a -
They are wound together.

Basically using multi meter, make sure there are no breaks in these two wires between the PCM and the port



See the pink with light blue and tan with Orange?
These are the serial BUS + and - wires
they go directly to your PCM and other modules 

Pins 15 and 16 at your PCM:

Last edited on Wed Nov 21st, 2018 06:14 pm by 410customs