The dongle is half the tool; the app is the other half
An adapter turns the diagnostic socket into something a phone can read, and it is bought as a pair: the dongle and the app. The dongle side comes down to the stated chipset and protocol coverage — CAN is universal on modern cars, but manufacturer-specific systems are not, and a cheap clone that answers only generic engine requests will look identical in a listing. The app side decides what you see, and several of the best-known ones are subscriptions. The third figure, rarely published, is standby draw: an adapter left in the socket can keep a module awake overnight. We compare chipset, protocols, iOS and Android support, app licensing and stated standby current.
ELM327 · Bluetooth Low Energy 4.0 · iOS and Android · power-saving mode stated · works with most OBD apps
The adapter most often recommended for iPhone users, and the one whose listing names the thing that matters when a dongle lives in the socket: a power-saving mode.
Best for: iPhone owners, who have far fewer working options than Android users.
For BimmerCode and MotoScan · Bluetooth 4.0 · iOS, Android and Windows · BMW motorcycles from 1998 stated
A coding adapter rather than a diagnostic one: officially recommended by BimmerCode and MotoScan, and the one BMW owners buy when they want to change what the car does rather than read why it complained.
Best for: BMW and Mini owners who want to code options, and BMW motorcycle owners using MotoScan.
≈ $93
All-system scan stated · exclusive ThinkDiag app · battery test · VIN identification · 12 languages
An adapter that behaves like a scan tool: the maker states an all-system scan with inspection reports, which is a different proposition from a code-reading dongle.
Best for: Someone who wants scanner-level coverage without a second screen in the drawer.
Bluetooth 5.1 · made for BimmerCode · advanced sleep mode and overvoltage protection · OBDLink app included
The adapter built for coding and safe to leave plugged in: Bluetooth 5.1, an advanced sleep mode, overvoltage protection, and its own app included rather than sold separately.
Best for: Anyone coding a BMW or Mini, and anyone who wants an adapter that can be left in the socket.
≈ $80
The quality of the circuit and the stability of the link decide whether the adapter works with the apps or drops out constantly.
A simple adapter paired with a free app reads engine codes for a few euros.
An adaptor left plugged in draws current permanently and flattens a battery in a week of standing. Stated automatic sleep is the least-quoted and most useful feature.
No: cheap adapters are poorly recognized by some apps. It is the most frequent problem with the format.
It draws current on standby and can flatten the battery of a little-used vehicle. Unplugging it between uses is more prudent.
Generally only the engine. The braking, airbag and transmission modules call for a dedicated tool.
Most apps allow it. That turns the light off without treating the cause, which will come back.
The basic functions are often free; advanced functions and code databases are frequently paid for.
Only if the vehicle has a compatible socket, which is not automatic. A connector adapter is sometimes needed.
That is the prudent practice for any connection to the vehicle network. Plugging in with the engine running is inadvisable.
It reads engine codes, defined by a standard common to all recent vehicles. Body, airbag or gearbox codes need manufacturer-specific protocols that most do not handle.
The adapter reads the engine and rarely anything else: the braking and airbag modules call for a dedicated tool. Very cheap models drop out with some apps, and left plugged in, one flattens the battery of a little-used vehicle.
There is no table here, and the reason is in the listings. The figure published most often across these 4 products is app, given by 2 of them — short of the four in five a column needs to compare rather than to display gaps. Each product page says what its own maker published.
Specifications: manufacturer sheets for garage tools and the matching Amazon product pages. Prices and availability: Keepa.
Most recent revision in this category: September 4, 2026.
