Car diagnostics is the process of identifying issues within a vehicle's systems using specialized tools and equipment. Technicians connect a diagnostic scanner to the car's onboard computer, which retrieves error codes that indicate specific problems. This helps in understanding the health of components like the engine, transmission, and emissions systems. By analyzing these codes, mechanics can pinpoint malfunctions and recommend necessary repairs. Regular diagnostics can prevent more significant issues and ensure that the vehicle operates efficiently. This process is essential for maintaining the performance and safety of a car, ultimately extending its lifespan.