Which OBD2 adapter works with iPhone?
Short answer: a Bluetooth Low Energy (BLE) adapter. The Vgate iCar Pro Bluetooth 4.0, about £20, is the safe choice.
An OBD-II adapter is the small plug that goes into the diagnostic port under your dashboard and turns the car's own data — speed, revs, temperatures, fault codes — into something a phone can read. Hundreds are sold, most of them for Android, and most of the ones that look identical behave very differently with an iPhone. What decides it is how the adapter talks to the phone.
Bluetooth Low Energy: the kind that works
iOS lets any app connect to a Bluetooth Low Energy device directly, without pairing it in Settings, and — crucially — lets the app reconnect to it in the background. That is what makes a drive record itself: the phone notices the adapter when you switch the ignition on and the app starts, with the phone still in your pocket.
BLE adapters are usually labelled "Bluetooth 4.0", "BLE", "Bluetooth LE" or "BLE 5.0". Ones known to work:
| Adapter | Notes |
|---|---|
| Vgate iCar Pro Bluetooth 4.0 (BLE) | The adapter OBDTrip is developed and tested with. Sleeps when the car does. About £20. |
| OBDLink MX+, LX and CX | Faster, dearer; the BLE side works directly. |
| Veepeak OBDCheck BLE / BLE+ | Works on either of its hardware revisions. |
| Other ELM327 BLE clones | Most use a standard serial-over-BLE layout and are recognised automatically. Quality varies. |
Classic Bluetooth: why most don't work
The cheapest adapters use the older Classic Bluetooth serial profile. You can spot them:
they pair in Settings with a PIN such as 1234 or 0000. Android lets any app open
that serial link; iOS does not. On an iPhone a Classic accessory can only be used if it is
MFi-certified by Apple and declares a protocol the app also declares, and almost no
cheap Classic OBD adapter is. The adapter pairs, then no app can talk to it — which is the single most
common reason an adapter "doesn't work with iPhone".
Wi-Fi adapters: why they fail on an iPhone
A Wi-Fi adapter makes its own little Wi-Fi network, and the phone has to join it. That causes three problems:
- No automatic recording. iOS won't let an app join a Wi-Fi network by itself in the background, so you have to open Settings and connect by hand on every drive.
- No internet while connected. The phone is on the adapter's network, which goes nowhere, so maps, music streaming and messages can stall or fall back to mobile data unpredictably.
- It drops when the phone sleeps or wanders back to your home network, and the drive stops recording.
Fine for reading a code on the driveway with the app open; no good for a phone that should record every drive without being touched.
How to tell what you've already got
- It appears in Settings → Bluetooth and asks for a PIN: Classic. It won't work unless it's MFi.
- It makes a Wi-Fi network called something like
WiFi_OBDII: Wi-Fi. - It never shows up in Settings → Bluetooth at all, but an app finds it: BLE. That's the one.
Don't pair a BLE adapter in iOS Settings. It doesn't need it, and an adapter paired there can be hidden from apps. If you did, choose Forget This Device and let the app find it.
Free to connect and see your car live; recording, fault codes and the used-car check are part of an OBDTrip subscription.
Does an adapter flatten the battery?
It draws a little power whenever it's plugged in. Good adapters, the iCar Pro among them, go to sleep when the car does. If the car will stand for weeks, unplug it.
Plug it in once, and every drive records itself
OBDTrip finds your BLE adapter on its own, recognises each car by its VIN, and records route, readings, fuel and fault codes on every drive — then reads and clears fault codes whenever you want. No account, and your drives stay on your devices.
