Sending a message to Bluetooth OBD adapter

I am a complete beginner to the MIT App Inventor. I am trying to create a simple application with just 2 buttons. Pressing on these buttons should send a serial command to the Bluetooth OBD adapter, and, eventually, to the car's J1850VPW bus. I found some example that communicates to the Bluetooth module connected to Arduino and send either "1" or "0" serial command to activate a LED connected to Arduino. I tried to enter the command that I want to send to the car as a text but it does not work. I am surely missing something here. How can I send the serial message to the OBD? Here are my blocks:


We have had a few OBDII projects:

The search facility will find more, if you search for OBDII.

As I recall, the AT commands might need CRLF ('\r\n') separators to get the OBDII unit to recognize end of command.

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