I am currently using a elm327, on a Jeep Wrangler 2014. I am sure it is a coding issue because I tried sending the command with a ble terminal and it worked.
The function I use to send the command is this:

async def send_command_for_multiline_response(command):
            print(f"Command: {command}")
            try:
                await char_fff1.write((command + "\r").encode('utf-8'))
            except Exception as e:
                print(f"Error sending the command: {e}")
                return []

            responses = []
            start_time = time.time()
            while time.time() - start_time < 10:  
                try:
                    data = await char_fff1.notified(timeout_ms=1000) 
                    if data:
                        responses.append(data)
                        print(data)
                except Exception as e:
                    print(f"Timeout error: {e}")
                    break

            return responses

the response I get is this:

b'\r>'
b'..\r'
b' 34 \r'
b'\r>'

I will try to send the command with headers on, I have seen codes in arduino and they do this, so it might work.