Code 12 will always show up first. It will show itself 3 times before any other codes are found. I will put a pic of the connector on soon. Codes will be cleared when the battery is removed or the engine fuse under the bonnet is disconnected. In responce to stewarts question, yes you could theoretically make an lcd readout but the flash system costs nothing. You can also buy a cable to connect that lists the codes, but this system is free and incredibly simple.