Bluetooth Chat App answering back same text I sent

Question

Im using one app to send data to the elm327 through bluetooth and I'm trying the AT Z command but everything I get back from the OBD2 is AT Z too, my code is missing something or its supposed to answer like that ? I expected the AT Z to return elm327 text (tested with playstore apps and thats what I got)

  // runs during a connection with a remote device
  private class ReadWriteThread extends Thread {
    private final BluetoothSocket bluetoothSocket;
    private final InputStream inputStream;
    private final OutputStream outputStream;

    public ReadWriteThread(BluetoothSocket socket) {
        this.bluetoothSocket = socket;
        InputStream tmpIn = null;
        OutputStream tmpOut = null;

        try {
            tmpIn = socket.getInputStream();
            tmpOut = socket.getOutputStream();
        } catch (IOException e) {
        }

        inputStream = tmpIn;
        outputStream = tmpOut;
    }

    public void run() {
        byte[] buffer = new byte[1024];
        int bytes;

        // Keep listening to the InputStream
        while (true) {
            try {
                // Read from the InputStream
                bytes = inputStream.read(buffer);

                // Send the obtained bytes to the UI Activity
                handler.obtainMessage(MainActivity.MESSAGE_READ, bytes, -1,
                        buffer).sendToTarget();
            } catch (IOException e) {
                connectionLost();
                // Start the service over to restart listening mode
                ChatController.this.start();
                break;
            }
        }
    }

    // write to OutputStream
    public void write(byte[] buffer) {
        try {
            outputStream.write(buffer);
            handler.obtainMessage(MainActivity.MESSAGE_WRITE, -1, -1,
                    buffer).sendToTarget();
        } catch (IOException e) {
        }
    }

    public void cancel() {
        try {
            bluetoothSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

Perhaps you're not reading enough – make sure you concatenate all fragments you read until you receive the actual prompt \r>.

ELM327 usually starts out in echo mode, where it echos every command you are giving to it, that may explain why you're reading it back. Use ATE0 to turn off this behavior.

In general, https://www.sparkfun.com/datasheets/Widgets/ELM327_AT_Commands.pdf explains all that.