Hello guys my problem is i cant recieve any data from OBD II to Raspberry Pi 3B+

Here the materials that i use:

Raspberry pi 3B+
ELM327 -> OBD II
Operating System of Raspberry Pi -> https://medium.com/@aadeshshah/pre-installed-and-pre-configured-raspbian-with-opencv-4-1-0-for-raspberry-pi-3-model-b-b-9c307b9a993a

Here the following step that i do:

Step 1: From sudo nano /etc/systemd/system/dbus-org.bluez.service i add

ExecStart=/usr/lib/bluetooth/bluetoothd -C
ExecStartPost=/usr/bin/sdptool add SP

Step 2:Reload the configuration file and Restart the service

sudo systemctl daemon-reload
sudo systemctl restart bluetooth.service

Step 3:Pairing


power on
power on
agent on
scan on
scan off pair

Step 4: Stablish connection

sudo rfcomm connect rfcomm0

Waiting for connection on channel 1 Connection from XX:XX:XX:XX:XX:XX to /dev/rfcomm0 Press CTRL-C for hangup

It connect but when i run screen /dev/rfcomm0 it can't recieve any data and also when i use cat /dev/rfcomm0 no data posted

This are the tutorial that i use https://www.youtube.com/watch?v=DABytIdutKk i change bind to connect command and its work but when i run screen /dev/rfcomm0 i cant get any data

I use the command atz but its just hang up

  • Hi @rika Salvador, Ah, let me see. (1) Rpi3/4 stretch/buster BlueZ5x is still buggy. I have wasted 10+ hours struggling to make a reliable setup. Search this forum for "Bluez" for more details. (2) I would suggest to first try this: SparkFun OBD-II UART - sparkfun.com/products/9555.
    – tlfong01
    Nov 17 '19 at 2:17
  • And if you are using an UART OBD2, you can talk ELM using terminal emulator such as these: RpiCuteCom or Win10RealTerm: (1) imgur.com/gallery/naolpGP, (2) raspberrypi.stackexchange.com/questions/105405/…
    – tlfong01
    Nov 17 '19 at 2:27
  • @tlfong01 thank you for your response, but it is possible to talk to the OBD II by enabling the UART in the raspberry pi?? because some of the projects that I work on is GPS tracking which talk by use UART communication protocol, but the serial is /dev/ttyAMA0 here's the link ::sparklers-the-makers.github.io/blog/robotics/… Nov 17 '19 at 3:01
  • Well, an UART device is an UART device. If device talks/hand shakes RS232/serial/ "AT", "OK", then it is 90% likely you are OK. I did once talk UART with GPS modules, along with many other UART modules including several configs of BlueTooth 4 serial module, RF433MHz serial module (RF12B), and so on. You might like to read my answer to the following question: Rpi UART to GPS Module Connection Problem raspberrypi.stackexchange.com/questions/98840/…. For the AMA/Serial/USB device confusion, please read my two references on RpiCuteCom above.
    – tlfong01
    Nov 17 '19 at 3:17
  • @tlfong01 Ok, thank you Nov 17 '19 at 3:21

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