OBD2/CAN BUS problems with send commands

Question

Hello

I'm developing application (Android). This aplication is connected to OBD2 compliant vehicle /CAN BUS and read data from it. I've done succesfully connection using OBDKey and read data using OBD message format. This message format is mode + pin

But now I have problems with CAN BUS How should I send command called message_id? What kind of AT commands I must send?