1.The V309 is one of the selling OBD II scanners on the market and is recommended by Scotty Kilmer, a YouTuber and auto mechanic. It can easily determine the cause of the check engine light coming on, quickly read and clear diagnostic trouble codes, read live data hard memory data, view ze frame, I/M monitor readiness and collect vehicle information. You can use it to check the trouble code and show code definition by yourself instead of taking the car to a mechanic shop. 2.OBDII Protocols and Car Compatibility: Many cheap scan tools do not really support all OBD2 protocols. This is not the case with the AD310 scanner as it can support all OBDII protocols such as KWP2000, J1850 VPW, ISO9141, J1850 PWM and CAN. This device also has extensive vehicle compatibility with 1996 USbased, 2000 EUbased and Asian cars, light trucks, SUVs, as well as er OBD2 and CAN vehicles both domestic and foreign. Check compatibility with your vehicle model before purchasing.