ANCEL BD310 Bluetooth OBD2 Scanner, 2-in-1 Car Diagnostic Scan Tool & Code Reader with App, Battery Test, Trip Analysis, Performance Test, for iPhone & Android, All 1996+ Vehicles

Why it's worth it

The BD310 is a small Bluetooth dongle that also works as a plug-in wired code reader with its own screen. It covers engine codes, live data, emissions readiness and battery voltage tracking, which handles most check engine light situations at a fraction of what the tablets here cost.

It works two ways, and that's the whole trick. Plug it into the port and it's a wired code reader with a display — no pairing, no app, no phone battery to worry about. Pair it over Bluetooth instead and the free app adds live graphs, freeze frame, EVAP and O2 sensor tests, HUD mode and trip data. Most dongles this size make you pick one or the other.

The code explanations are written for people who aren't mechanics. You get a plain-English description of the fault plus built-in search, so a code arrives with some context rather than as a bare number. If this is your first scanner, that's worth more than any spec on the box. Published reviews have singled the BD310 out for exactly this kind of approachability.

From our review of 7 obd2 scanners, by Genevieve Dubois, Home & Living Expert

What we like

• +It works two ways, and that's the whole trick
• +The code explanations are written for people who aren't mechanics
• +Battery monitoring is the quiet reason to keep it in the glovebox
• +It covers all ten standard OBD2 modes, including I/M readiness

What to know

• –It's engine-only, full stop
• –The good features live in the app