Vgate vLinker BM

Inside, the BM is tuned for long, heavy sessions. Vgate gives it a USART buffer of up to 2K bytes, raises the serial rate to 230.4 kbps and accepts OBD requests up to 1024 bytes long. Those figures matter for the long frames coding tools send, where the small buffer of a cheap clone chokes and the app reports a lost connection.

The radio is Classic Bluetooth 3.0. That is the serial-style link Android and Windows have always spoken, and it is the reason iPhones cannot use it. Apple only lets ordinary apps reach Bluetooth LE accessories, so the BM never appears on an iPhone at all.

• BimmerCode: Vgate states 100% coverage of the vehicles the app supports, and the BimmerCode team recommends the BM.
• BimmerLink: fault codes across modules, live values and model-specific extras.
• General OBD2 apps: Torque Lite and Pro, Car Scanner, OBD Fusion, DashCommand, JScan and inCarDoc on any 1996-or-newer car.

Bi-directional tests, where the app asks a module to run a component, depend on the app and the car rather than on the adapter. The BM passes the commands along; the software decides what it can offer on your model. For what a Bluetooth link can and cannot do in general, the ELM327 Bluetooth guide covers the basics.

That makes the choice simple for a lot of owners. If every phone in the house runs Android, the BM covers the whole BimmerCode vehicle list, old chassis included, with no split between models.

A few habits make older-car coding go smoothly:

1. Hook up a battery charger or maintainer, because an E-series with a tired battery sags quickly with the ignition on.
2. Let BimmerCode identify the car and back up each module before you change a value.
3. Keep the phone on charge and stop the screen from sleeping mid-session.
4. Change one setting at a time, then test it before moving to the next.

Retrofitted modules can confuse the app's picture of the car, so let it scan rather than assuming factory spec. The car compatibility guide covers how far ELM327 adapters reach on BMW and other brands. If an iPhone joins the household later, the vLinker BM+ is the same idea on Bluetooth LE.

1. Plug the BM into the OBD port under the dashboard and switch the ignition on.
2. Open Bluetooth settings on the Android phone and look for the vLinker.
3. Pair it, entering the PIN if prompted.
4. Open BimmerCode, BimmerLink or Torque and choose the vLinker as the adapter.
5. On a Windows laptop, pair it the same way; Windows assigns a COM port that ELM327 software can select.

Once paired, the BM can live in the car. Vgate quotes 51 mA while working and as little as 3 mA asleep, with automatic sleep when the car goes quiet. It has up to three ways to wake, including a change in battery voltage and activity on the OBD bus.

For scale, 3 mA for a week comes to about half an amp-hour, which a healthy battery hardly notices. Stored cars and weak winter batteries are another matter, so unplug it before a long layup.

Over-voltage, over-current, over-temperature and battery-drain protection guard the car and the adapter against spikes from a jump start. The ELM327 connection fixes cover the case where pairing works but the car stays silent.

The BM is the lightest of the group at 25 g and the one to pick when nobody in the car uses an iPhone. The BM+ adds iPhone support with the older-chassis caveat. The CX carries the app maker's own endorsement and OBDLink's support.

• Pick the BM for an Android phone, a Windows laptop and any BMW that BimmerCode supports, old or new.
• Pick the BM+ if an iPhone might ever do the coding.
• Pick the CX if you want the adapter BimmerCode is designed around.

The BM fits when your phone runs Android, your car runs on 12V, and the app you plan to use accepts Classic Bluetooth adapters. BimmerCode, BimmerLink and Torque on Android all do.

None of these three is a Ford tool; for FORScan and MS-CAN, the vLinker FS range fits better. The Vgate and OBDLink comparison sets the two brands side by side.