Here you can see the error message I get when I try to read the ODB port on the engine.
Pins 4 and 5 are connected. I get +5 volts when I measure between 4/5 and 7 and 4/5 and 16, so it seems like the device is working.
I tried it on the engine, and on my car, which is a Subaru Forester with an ODB-II port.