Originally Posted by karimz (Post 2258573)

I was about to purchase the Carista app but found instructions to do it using a terminal app like hyper terminal or putty (I used putty). I got the instructions on a prius forum but I can confirm that it worked for my 2014 FR-S. I did this last night actually. You need an ELM327 to USB cable (had one laying around but they can be found on ebay fairly cheap). The instructions on the other forum said to set the baud rate to 115200 but I could only get it working at 38400. Try different baud rates if you see gibberish when you type.

Enter the following commands:
AT SH 7c0 (hit 'Send')
Returns: OK

21a7 (hit 'Send')
Returns: 61 AC C0 (meaning beep enabled)

3ba700 (hit 'Send')

21a7 (hit 'Send')
Returns: 61 AC 00 (meaning beep disabled)

That's it! The driver's side seat belt warning won't beep anymore (I haven't tested the passenger side, but I imagine there's a separate command for that). I believe the settings cycle so if you wanted to re-enable it, I imagine you'd just have to re-enter the same commands again, but don't quote me on that as I haven't tested it. You could probably follow these instructions on an android device if you have a bluetooth OBD2 adapter and a terminal app. I have an iPhone and couldn't find an app that would let me send commands.