Deductions & credits

Yes, since you did not sell the vehicle, you'll tell TurboTax that it was converted to personal use. the percentage of business to personal does not matter at this point. 

When you DO sell the vehicle, you may need to deal with depreciation recapture. 

When you use the Standard Mileage Rate, there is a "Depreciation Equivalent" in each mile. 

You determine the depreciation taken by both businesses and use that if you need to compute depreciation recapture. 

At the time you sell, you'll also need to average the business use including when it was used for company A.

Example, you averaged 20% business use for Company A and 30% for company B so 25% business use.

The basis was 20,000, you took 5,000 depreciation so the adjusted basis is 15,000.

If you sell it for more than 15,000, (up to 20,000) 25% of the profit will be deprecation recapture.