When calculating "UCC at the beginning of the year" for car used for business purposes, do you minus 30% off original purchase price each year or the remaining balance?

Is this the first year of using the vehicle for business purposes? Or have you used it in the past and just not claimed CCA on it?

If you began using your vehicle for business use in a previous year and have "never' claimed CCA on it, you can enter the UCC as the Fair Market Value (FMV) on the day you started using it for business purposes. 

There is no need to reduce your CCA if you have never claimed CCA on this particular vehicle.