Audi Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry that you have not been helped yet. I just came online and saw your question
Did you check the fuses with a voltmeter or just visually? Do you have a voltmeter for testing and good understanding of automotive electrical and computer systems?
I will need the vin number to pull the schematics for the MMI to see what may have been fried by the reverse polarization.