Connect the adapter

Choosing the connection type your phone supports, pairing the adapter and turning on the automatic start when the car turns on.

The Connection screen opens from the connectivity card on the home screen, or from the Connection row in Settings. This is where the adapter is found, paired and saved.

When you open the screen with no active connection, the app starts scanning on its own.

  1. Choose the connection type

    The tabs show the connection types your phone supports. On Android there are four: Bluetooth, BLE 4.0+, Wi-Fi and USB. On iPhone there are two: BLE 4.0+ and Wi-Fi.

    The absence of the other two on iPhone is a limitation of iOS, not of the app. Classic Bluetooth adapters, the ones that ask for a PIN such as 1234, do not work with an iPhone.

  2. Authorize Bluetooth

    On the first tap on refresh, the app explains why it needs Bluetooth and only then opens the system request. Tap Allow on both screens.

    On the USB tab Bluetooth is not requested, because a cable connection does not depend on it.

  3. Scan and connect

    Tap the refresh icon to the right of the list. The scan takes about twelve seconds on Bluetooth and on BLE. Devices already paired come first, marked Paired, and new ones show up as Not paired as they are found.

    Tap the adapter you want. On classic Bluetooth, if it is not paired yet, the app pairs it there and then and waits up to thirty seconds. The default PIN is usually 1234 or 0000.

  4. Accept the requests that come after connecting

    Once the connection is established, the app requests what starts to make sense at that point: location, with the Allow all the time and While using options, and notifications.

    Choose Allow all the time. That option keeps the trip recording going with the screen off and saves where the car was parked.

  5. On Wi-Fi, connect through the phone first

    The Wi-Fi tab shows no device list. Join the adapter's network from the phone's Wi-Fi settings first. On Android there is a button that opens that screen directly; on iPhone the path is Settings, Wi-Fi and the adapter's network.

    Back in the app, check the IP Address and the Port and tap Connect. The fields carry examples, such as 192.168.0.10 and port 35000, and the app tries the most common addresses on its own, filling the field in when it finds the right one.

    The tab itself warns about the limitations of this kind of adapter: it does not allow automatic connection, and the phone may treat the adapter's network as having no internet access and block mobile data while connected to it.

  6. On USB, use an OTG cable

    Plug the adapter into the OBD port and connect the cable to the phone through an OTG adapter, which is essential on phones with USB-C.

    Baud rate stays on Auto, which tries the common speeds and remembers the one that works. The Advanced section, with VID (hex), PID (hex) and Driver, is only needed when the adapter is not detected; leave the fields blank for automatic detection.

    When Android asks which app to open, select the option to use it by default: that is what makes the app open on its own the next time the cable is connected. With a cable the phone powers the adapter and does not charge; on long trips, use a powered Y cable plugged into a 12 V socket.

  7. Turn on the automatic start when you get in the car

    A feature available on Android only, from version 8 onwards. On the Start the app when the car turns on card, tap Select your car's Bluetooth and choose your vehicle's stereo from the list.

    The list carries only audio devices already paired with the phone. If your car is not there, pair the phone with it in the Android Bluetooth settings and come back to this screen.

    The app marks this feature as Experimental. If it does not work on your car, create a routine on the phone itself to open the app when the vehicle's Bluetooth connects.

  8. Check what was saved

    The card at the top starts showing Saved OBD-II adapter with the device name. Auto-reconnect to adapter comes switched on, and it is what connects the app from then on.

    On Android, also turn on Disable battery optimization. Without that exemption the system can end the recording in the background.


If something goes wrong

If the adapter asks for a PIN such as 1234 and shows up in the phone's own pairing list, it is classic Bluetooth, and iOS does not make that kind of connection available to apps. The limitation belongs to the system, and no app setting gets around it.

For iPhone, look for an adapter that states Bluetooth 4.0 or later, also called BLE, or a Wi-Fi adapter.

  • Make sure the ignition is on. Many adapters do not power up without it.
  • Make sure the phone's Bluetooth is on. If it is off, the app says so and offers to open the settings.
  • On classic Bluetooth, pair the adapter in the phone settings before scanning.
  • If the adapter has been paired with another phone, disconnect it there. Most accept only one connection at a time.
  • Pull the adapter out of the OBD port, wait ten seconds and plug it back in.

The adapter does not implement the ELM327 protocol and works only with its manufacturer's own app. There is no way for Car 2 Home to talk to the car through it.

The warning offers the OBD Adapters button, which opens the list of compatible models.

Check that the IP Address and the Port are filled in. With either one blank, the button does not run the connection and the screen shows no warning. If you do not know the address, check the adapter manual: the most common ones are 192.168.0.10 and 192.168.4.1.

Make sure as well that the phone is connected to the adapter's network and not to the home network.

The link with the car is local to each device and does not follow the account. On the new phone the Reactivate auto-start here card appears: tap Reactivate and confirm the link.

The list shows only audio devices already paired with the phone. Pair the phone with the car stereo through the Android Bluetooth settings and come back to the screen.

If the feature still does not work, use a routine on the phone itself to open the app when the car's Bluetooth connects. The screen suggests that alternative because the feature is experimental.

Check the OTG cable and try again. If the app says USB access was denied, unplug and replug the adapter so that the system asks again.

If the adapter still is not detected, fill in VID (hex) and PID (hex) in the Advanced section with the values given by the manufacturer.


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