You can read the trouble codes on your '92 Nissan right from home without using any specialized tools. The On-Board Diagnostics I computer (OBD I) receives and stores trouble codes. It alerts you to malfunctions by illuminating warning and service lights on the Nissan's instrument panel. Look up the meaning of the codes in the Nissan's owner's manual.
Put the key into the ignition and turn it to the "on" position.
Locate the trim panels in the front part of the center console. Remove them using a screwdriver. Find the Nissan's computer, which is attached to a bracket on the transmission tunnel.
Rotate the diagnostic mode selector using a screwdriver. This is a small hole that can be found on the side of the computer. Turn it until it won't go any further. Next to the hole are red and green LED lights.
When these lights quickly flash three times, immediately turn the diagnostic mode selector counter-clockwise until it won't turn any further.
Notice the flashing red and green lights and count how many times each of them flash. The red lights are the first digit and the green lights are the second digit. So, if the red light flashes four times and the green lights flash two times, then the error code is "42."
Turn the vehicle off and put the trim panels back in place. Look up the code numbers in the owner's manual to understand their meaning.
