FORScan is unable to connect to my vehicle, why?
If you use latest version and your vehicle is Ford, Mazda, Mercury or Lincoln after 1996, then most likely your ELM327 has problems with support of certain protocols. Unfortunately, china clones have quite bad quality, escpecially recent ones. From experience, protocol SAE J1850 PWM is most problematic. However, our users had indcidents with ISO 9141 and CAN bus too.
It should be also counted that ELM327 has 3 almost independent cirucits: one for SAE J1850 PWM/VPW, second one for ISO/KWP and last one for CAN. Your adapter may have problems with e.g. J1850 PWM, but in the meantime it will work OK with rest 2 bus. This is why users who claim that their ELM327 is OK because "it works on some Hyundai, Nissan etc" may be wrong.