What is the purpose of a scan tool?

• A. To read vehicle diagnostic codes
• B. To measure tire pressure
• C. To adjust the air conditioning
• D. To test battery voltage only

Answer: (A)

A scan tool’s main job is to read the diagnostic trouble codes from the vehicle’s onboard computer systems. It connects to the car through the OBD-II port and communicates with the engine control module and other control modules to pull codes that point to where a fault is occurring. These codes guide you to the likely failing system or sensor and, with the tool, you can also view live data streams from sensors, check freeze-frame information about the conditions when the fault was stored, and (on capable tools) run built-in tests to help confirm repairs. After you fix the issue, the scan tool can clear the codes so the system can recheck for new problems.

Measuring tire pressure, adjusting the air conditioning, or testing battery voltage using a dedicated tool are different tasks handled by their respective tools. A scan tool isn’t primarily used to measure tire pressure or adjust HVAC settings, and while some scan tools may display voltage data, their core purpose is reading and interpreting diagnostic codes to guide troubleshooting.