Funny because I can empathize. Just google "LC-1 7.4" and you'll see how common this problem is. The LC-1 is so fucking temperamental that it about made me pull my hair out getting it to work right. Now, after all these years, it will blink E4 on about one out of every 10 (1 of 10) startups and won't reset unless I turn the car off and immediately back on. Grounded right to the engine block EXACTLY per the instructions and I use that fancy heat sink they sell as well. Now that money isn't as much of an issue, I am considering a different brand based on pure hatred. Innovate does have the new all digital system out which does away with the LC-1 so who knows.
P.S. - Having to buy the USB to serial port adapter was equally as ridiculous.