I am required to have a vehicle for my job and am reimbursed for mileage and for a set amount for car maintenance monthly. I have a box 40 with an amount on my T4, which I assume is the amount I was reimbursed for these expenses. How do I know if I paid tax on this reimbursement and if I was, how do I claim those car expenses? I don't know what a T2220 is but I am obligated per my contract to have a vehicle and use it as a condition of my employment.
If you want to claim motor vehicle expenses for which you have been reimbursed for, you must get that T2200 - Declarations of Conditions of Employment completed and signed by your employer. On the form, it should clearly state the amount of any reimbursements which have been included in your taxable income. Without this form, CRA clearly states you cannot claim your Employment Expenses even if your contract require you to use your own vehicle for employment purposes.
The following CRA guide explains in further detail Employment Expenses, as well as having a link to the T2200 form.