That depends on the scanner. Typically they are plugged in to either the USB port or the parallel port, depending on how the scanner is designed.
You can find your 1994 Nissan Maxima auto scanner plug on the bottom of the drivers side dashboard. The auto scanner plug will be to the left of the steering column.
plug scanner's cord into the USB port
External Device
Diagnostic plug. Diagnostic connector. Data link connector.
Buy a scanner, put the drawing onto it, plug it in to the computer, and follow the scanner's instructions to scan it.
You need to plug an OBD scanner into it.
there's a cap up the lighter with a engine, take it of and the plug is there
Black OBD2 plug, located under steering wheel, below panel .
The plug you are looking for is at the of the plastic shield that is just below steering column.
plug it in and follow the directions
Because most scanners are Plug and Play.
inside the fuse box at the bottom