2012 Honda Fit, base model. 79k miles. Deceased uncles car. Battery was dead. Jumped and radio asked for code. Found it on sticker in glove box. Radio was working fine. Bringing car home 1.5 hours away we had to jump it 3 times total. One start attempt after some highway driving the car trying to start would not, whole electric system (all lights) would go off between motor failed start attempts before jumping. After, this jump unit turns on, no sound. All buttons work. (holding down 1&6 then power on goes into diag mode, one preset tests all buttons). In FM mode the preset #s don't change anything, stays on same station, with no sound. Will not seek to another station, usually no volume number display change. CD thinks it plays, counts, no sound output. Tried aux input, no sound. Tried removing both radio fuses, no change, didn't even ask for code. Disconnected battery, unit asks for code, then no sound again. Anything I can do in DIAG mode?
my YT video asking for help: