KlaroWhich adapter to choose
Klaro needs an OBD2 adapter plugged into your car's diagnostic socket. It does not come with the app, and they are not all equal — here is what actually matters.
Bluetooth rather than Wi-Fi
A Wi-Fi adapter creates its own network and your phone joins it: the adapter becomes your gateway, and you lose internet access for as long as you stay connected. Harmless in a garage, annoying if you want to look up a part or send someone a code mid-diagnosis.
Over Bluetooth, the link to the adapter and your network access coexist. That is why we recommend Bluetooth.
On iPhone: Bluetooth Low Energy is mandatory
This is the most common buying mistake, and the most expensive. iOS reserves the classic Bluetooth serial profile for MFi-certified accessories: an ELM327 adapter using Bluetooth 2.0 or 3.0 — the cheapest and most widespread — will never connect to an iPhone, whatever the app.
You need a model advertised as Bluetooth 4.0, 5.0 or "BLE". On Android both work: Klaro accepts classic serial as well as BLE.
What to check before buying
Bluetooth 4.0 or later
Essential on iPhone, no downside on Android. If the product page is vague about it, move on.
ELM327 v1.5
Many adapters claim "v2.1": that firmware version does not exist on the ELM side. Honest v1.5 units are generally more stable.
Your car must support OBD2
That covers petrol cars sold in Europe since 2001 and diesels since 2004.
Standby power draw
An adapter left plugged in keeps drawing current. Unplug it if the car sits for several days, or pick a model with a switch.
Our recommendation
A Bluetooth Low Energy adapter, compatible with both iPhone and Android.
This is an affiliate link: if you buy through it we earn a small commission, at no extra cost to you. It does not change what we recommend — an adapter that does not work would mostly earn us bad reviews.
Once it is plugged in
Switch the ignition on, open Klaro, choose Bluetooth: the app scans for adapters in range and connects. Fault codes appear in plain words, with how serious they are.
