I was a police officer recruit for 2016 and had to use my personal vehicle to travel to the police academy. I was informed i can use the mileage on my tax return. I entered the mileage used, but form 2106 it is asking for the mileage and the cost of the vehicle. I am not sure on what to enter for that.
It sounds like you're being asked this in the review screens, so I'd recommend going back to the initial entry and making sure to enter this info there as asked. I'll include instructions below.
Also, you must enter the mileage under "business" not commuting miles, on the entry screen for the mileage. The software also does ask about the vehicle, per the IRS rules, but again I'd recommend entering this in the initial entry area. To do so: