You asked: If my employer combines my mileage reimbursement with my work payment on my w2 form, can TurboTax software separate them so I don’t owe tax on the mileage?

[loisstack]

The employer says I owe taxes on both my work payment and my mileage reimbursement, and refuses to report them differently.

[SweetieJean]

Your employer is correct.  W-2 employees can no longer deduct mileage, and must pay taxes on any reimbursement.

[KrisD15]

There was a time when an employee could write off cost of mileage as a work expense, but that is no longer available. 

If your employer is paying you as a W-2 employee, they would need to supply you with a vehicle, or pay you as a contract worker on a 1099 (as if you are self-employed) or include payment in your wages. 

Since they are including the payment as part of your wages, you can't separate the expense out and you'll pay tax on it. 

[AmeliesUncle]

Because your employer is doing it that way, there is nothing you can do.

However, you might consider pointing out to your employer that if they start reimbursing mileage under an "Accountable Plan", it will save taxes for BOTH you AND your employer.