Scan Tool Does Not Communicate With UART Data Line

Scan Tool Doesn't Communicate With UART Data Line (Oldsmobile) (Part 1 Of 3):

Scan Tool Doesn't Communicate With UART Data Line (Oldsmobile) (Part 2 Of 3):

Scan Tool Doesn't Communicate With UART Data Line (Oldsmobile) (Part 3 Of 3):