COMPUTER DIAGNOSTICS REFERS TO THE PROCESS OF USING SPECIALIZED TOOLS AND SOFTWARE TO ASSESS THE PERFORMANCE AND HEALTH OF A COMPUTER SYSTEM, WHETHER IT'S A VEHICLE'S ONBOARD COMPUTER OR A PERSONAL COMPUTER. IN VEHICLES, IT INVOLVES CONNECTING TO THE CAR'S COMPUTER VIA THE OBD-II PORT TO RETRIEVE DIAGNOSTIC TROUBLE CODES (DTCS) AND OTHER DATA RELATED TO VARIOUS SYSTEMS LIKE THE ENGINE, TRANSMISSION, AND BRAKES. FOR GENERAL COMPUTER DIAGNOSTICS, TOOLS ARE USED TO CHECK HARDWARE AND SOFTWARE COMPONENTS FOR ERRORS AND PERFORMANCE ISSUES.