Use specification of SMART OBDII-16 connector, OBDII－16C connector and OBD CAN connector
1. SMART OBDII-16 connector is used for testing the vehicle model without CAN BUS system (if the 6 and 14 pin positions of 16PIN diagnostic socket is without sheet metal, it indicates that the vehicle is without CAN BUS system).
2. OBDII-16C connector is used for testing the non CAN BUS systems of the vehicle model with CAN BUS system (if the 6 and 14 pin positions of 16PIN diagnostic socket is with sheet metal, it indicates that the vehicle is with CAN BUS system). 
3. OBD CAN connector is used for testing CAN BUS system (if the 6 and 14 pin positions of 16PIN diagnostic socket is with sheet metal, it indicates that the vehicle is with CAN BUS system).

When is CANBUS connector used?
1. Must use CANBUS connector when using diagnostic software OBD CAN.
2. Must use CANBUS connector when testing CAN BUS systems of BENZ, VW, RENAULT, and MAZDA.