In Toyota models made after 1996, the OBD port, or on-board diagnostic port is used by mechanics to scan the vehicle’s computer system for trouble codes, in an effort to diagnose and fix any problems.
For older models, such as the 1992 4Runner, your mechanic will likely have a scan tool to find the codes, but an OBD scan tool that is now standard to run trouble codes won’t work on a Toyota from 1992 or earlier. In order to properly diagnose any problems with your Toyota 4Runner, take the vehicle into a Toyota dealership. Toyota technicians will have the proper tools to diagnose and fix your 4Runner.