How to connect an OBD2 scanner to your iPhone

An OBD2 adapter plugs into a port under your dashboard and lets your iPhone read live engine data and trouble codes from your car's computer. Connecting one takes about a minute once you know two things: which kind of adapter works with an iPhone, and that Bluetooth LE adapters connect inside the app, not in iOS Settings.

What you need

• A car with a standard OBD2 port. Most US vehicles from 1996, European petrol cars from 2001, diesels from 2004 and most cars worldwide from around 2008 have one.
• An ELM327-compatible adapter that connects over Bluetooth LE (4.0 or newer) or Wi-Fi. Classic Bluetooth adapters, often sold for Android, can't connect to an iPhone.
• Odo installed on an iPhone running iOS 18.6 or later.

Find the OBD2 port

The port is a 16-pin connector, usually under the dashboard near the steering column and within arm's reach of the driver's seat. On some cars it sits behind a small cover. Push the adapter in firmly: a loose fit is a common cause of dropped connections later.

Connect a Bluetooth LE adapter

1. 1

   Start the engine

   A running engine gives the best results. Some cars also respond with the ignition on and the engine off. Electric vehicles need to be in Ready.

2. 2

   Don't pair it in iOS Settings

   Bluetooth LE adapters connect directly through Odo. If the adapter is listed under iOS Settings → Bluetooth, tap (i) and choose Forget This Device.

3. 3

   Scan in Odo

   Open Garage → OBD II and tap Scan. Stay in the car so the adapter is in range. It should appear within 30 seconds, under likely OBD adapters or, if it uses an unusual name, further down the list.

4. 4

   Tap to connect

   The first connection takes 10 to 30 seconds while Odo sets up the adapter and asks the car which readings it supports.

Connect a Wi-Fi adapter

1. 1

   Join the adapter's network

   With the engine running, open iOS Settings → Wi-Fi and join the adapter's network.

2. 2

   Add it in Odo

   In Garage → OBD II, choose the Wi-Fi option. Most adapters use the address 192.168.0.10 and port 35000, which Odo fills in by default.

3. 3

   Connect

   Tap to connect. If iOS later drops the adapter's network, rejoin it in Settings.

What you'll see

• Dashboard: the readings that matter most, with a plain-language explanation for each.
• Live: every standard reading your car reports, grouped by system.
• Codes: stored, pending and permanent trouble codes, with explanations and a code history.
• Adapter: connection details and a debug log you can share with support.

Odo reads your car's VIN and matches the session to the right vehicle in your garage. From then on it reconnects automatically when the app opens, when a trip starts and when CarPlay connects.

If the adapter doesn't appear

• Check it's firmly plugged in and the ignition is on. Some adapters take up to 30 seconds to start advertising.
• Forget the adapter in iOS Settings → Bluetooth if it's listed there; pairing in iOS blocks the app from connecting.
• Confirm it's a Bluetooth LE adapter, not a classic Bluetooth one, and not an adapter locked to its maker's own app.
• Still stuck? See our guide to adapters that connect but show no data.