I had to request the manual by CHAT, but it was emailed to me right away. There is a testing program for it using the USB connector, but all of the information is in Chinese, so if you don't read Chinese, it is of little value. This is strange since I'm sure that the OBDII is generating ENGLISH ASCII responses.. but they are converted to Chinese. Guess I'll have to create my own program from scratch. However, the board worked fine as delivered and meets my needs as a local substitute for having a car in my basement :-) .