The CTool is a stand alone unit for reading and clearing codes from your OBD II port (and turning the check engine light off). A computer is not required to interface with your vehicle. If you are only looking to turn your check engine light off and retrieve error codes, this is the unit you want. Fix the problem yourself or keep your mechanic honest. This unit is compatible with most OBD II compliant vehicles (1996 and newer) although it does not work with CAN protocol vehicles. Usually ships next business day.