Investors & landlords

I sold a truck in the Spring of 2021.  I I sold it for more than its book value.  It was a cash sale with just one payment.  My Turbo tax is wanting me to fill in 6252.  But the app keeps coming up with a precalculated depreciation which it says is too high.  I have gone through and reentered the sales info several times.  the error persists.