What is the main function of a code reader in a vehicle?

The primary function of a code reader, also known as an OBD-II scanner, is to retrieve trouble codes from the vehicle's computer system. These trouble codes indicate specific issues or malfunctions within various systems of the vehicle, allowing technicians to diagnose problems more efficiently. The information provided by the code reader guides the technician in identifying the root cause of a vehicle's performance issues or warning lights that may appear on the dashboard.

Having the ability to access and interpret these trouble codes is crucial in modern automotive diagnostics, as it streamlines the repair process and helps prevent unnecessary trial-and-error repairs. The code reader connects to the vehicle's onboard diagnostics (OBD) port, facilitating communication with the engine control unit and other relevant modules.

In contrast, other functions such as changing tire pressure settings, testing battery voltage, or adjusting fuel mixtures relate to different types of tools or diagnostic equipment that serve specific purposes, rather than the core function of a code reader.