Mismatch code 2008 VE

[Dboy82]

Hey guys, happy new year to all. So a mismatch code has presented itself in my 2008 ve. I have worked on this for weeks now. It's because the line level converter was wired incorrectly. This is running to a sub and amp. All has been working perfectly until one day when my misses closed her door it just went dead? Today I got my hands on a tech2. Now I am not computer eliterate by any means and I know this device will need to be ran with one. Done a whole lot of reading up on it, just want to know if anyone has had any experience doing this and can I get any advice? Preferably step by step instructions with illustrations...lol