Vehicle partially used for business since 2005 - always took standard mileage deduction

I have a 2005 SUV that I've used part-time for business since 2005.  I take the standard mileage deduction each year using the actual mileage, splitting it % wise between business and personal.  The suv got a blown head gasket mid 2022.  It's sitting in my front yard since then.  I don't know if I will repair it, donate it or sell it for $1-2K.   I had to buy a new truck.  

 

TT is now trying to get me to calculate and pay back the depreciation of the old suv SINCE 2005.  That doesn't seem right and if it is, that's a huge amount of money!  Help!!!