VIN check

I check the VIN for my unit, but I get the 'You have exceeded the amount of VIN lookups for this unit. Try again in a week' message. Why?

Each identification number is checked. If the VIN is correct and has not been verified before, it is considered to be unique. For a unit, it is allowed to check maximum of three unique numbers per week. If more than three unique VINs were entered, the system issues a corresponding message.