EVMetricsOBD

Compatible OBD Adapters

No proprietary hardware required. Any ELM327-compatible adapter works — but not all are equal. This guide explains what to buy and what to avoid.

Overview Showcase Vehicles Vehicle Data API Use Cases Adapters ECUs

Connection types

Three ways to connect

All three connection types use the same ELM327 AT command set internally. The differences are range, reliability and use case.

Bluetooth LE

iPhone · iPad · Mac

Default. Pairs instantly, no Wi-Fi setup. 10 m range inside a car. Best for iPhone and iPad use by EV owners. The most widely available adapter type.

USB Serial

Mac · iPhone (via adapter)

Wired FTDI, CH340 or CP210x USB-to-serial. Rock-solid for sustained workshop sessions. Zero dropped connections, higher throughput. Recommended for professional Mac use.

Wi-Fi

iPhone · iPad · Mac

TCP socket to a Wi-Fi ELM327 access point. Useful where BLE range is marginal. Requires manual Wi-Fi network join. Less convenient than BLE for daily use.

Bluetooth LE adapters

For iPhone, iPad and Mac

These adapters use Bluetooth Low Energy (BLE / Bluetooth 4.0+), which is required for iOS/macOS CoreBluetooth compatibility. Classic Bluetooth (BR/EDR) adapters do not work on iPhone or iPad.

OBDLink

OBDLink MX+

Best overall

The gold standard for professional ELM327 work. Uses OBDLink's STN2120 proprietary chip — not a generic ELM327 clone. Exceptional CAN coverage, works with all protocols including CAN 11-bit and 29-bit extended, and handles multi-frame ISO-TP responses reliably.

Chip: STN2120

Protocol: CAN + legacy

Connection: BLE + classic BT

Price: ~£80–£100

iPhone iPad Mac Extended CAN ISO-TP multi-frame

OBDLink

OBDLink CX

Recommended

BLE-only version of OBDLink hardware at a lower price point. STN2255 chip. Excellent protocol support and fast response times. No classic Bluetooth — pure BLE, which is exactly what iOS needs.

Chip: STN2255

Protocol: CAN + legacy

Connection: BLE only

Price: ~£50–£70

iPhone iPad Mac Extended CAN

Vgate

iCar Pro BLE

Recommended

One of the most popular BLE OBD adapters. Good protocol support, reliable on CAN vehicles. Uses a Vgate-sourced ELM327 v2.1 variant. Works well with JLR I-Pace and most CAN-based vehicles.

Chip: ELM327 v2.1 variant

Protocol: CAN + legacy

Connection: BLE

Price: ~£20–£30

iPhone iPad Mac Extended CAN (some)

Carista

Carista OBD2 Adapter

Recommended

Clean BLE adapter with solid firmware. Carista's own name is on the whitelist in the app and it is explicitly tested. Good for general use; the companion Carista app is not needed — EVMetricsOBD works independently.

Chip: Custom ELM327-based

Protocol: CAN

Connection: BLE

Price: ~£20–£35

iPhone iPad Mac

Vgate

vLinker MC+ (BLE)

Budget pick

Budget BLE adapter with broader protocol coverage than older Vgate models. Good entry point if cost is the priority. Works for most CAN vehicles including I-Pace when using standard protocols.

Chip: ELM327 variant

Protocol: CAN + legacy

Connection: BLE

Price: ~£15–£25

iPhone iPad Mac

Generic (Amazon / eBay)

Cheap "ELM327 v1.5" clones

Avoid

Many cheap adapters advertise "ELM327 v2.1" but ship with counterfeit or cut-down firmware. These clones often fail on multi-frame ISO-TP responses (needed for UDS Service 22), drop CAN 29-bit extended frames, or silently corrupt ATSH responses. Not recommended.

Chip: PIC16F627 (fake)

Protocol: CAN (partial)

Connection: BLE (varies)

Price: £5–£12

iPhone (sometimes) UDS Service 22 Multi-frame ISO-TP

Classic Bluetooth (BR/EDR) adapters do not work on iPhone or iPad. iOS CoreBluetooth only supports BLE (Bluetooth 4.0+). If your adapter does not advertise BLE / Bluetooth LE / Bluetooth 4.0+, it will not appear in the app's device scanner on iOS. It may work on Mac via the macOS Bluetooth stack if the device supports SPP.

USB Serial adapters

For Mac (and iPhone / iPad via USB-C)

Wired USB eliminates Bluetooth reliability concerns entirely. Recommended for workshop use, sustained multi-hour sessions and any scenario where connection stability is critical.

OBDLink

OBDLink SX

Best USB pick

USB-only version of OBDLink hardware. STN1170 chip delivers faster response times than any ELM327 clone and handles all CAN variants cleanly. Ideal for Mac workshop sessions where the car is stationary.

Chip: STN1170

Interface: USB-A (virtual COM)

Driver: Plug-and-play on macOS

Price: ~£25–£40

Mac iPhone (USB-C adapter needed) All protocols Multi-frame ISO-TP

Vgate

vLinker FS (USB)

Recommended

Popular USB adapter among the FORScan community. Good CAN coverage and solid firmware. Uses CH340 USB-to-serial chipset which is well-supported on macOS without additional drivers on recent macOS versions.

Chip: ELM327 + CH340 USB

Interface: USB-A (virtual COM)

Driver: CH340 (included / macOS native)

Price: ~£15–£25

Mac iPhone (USB-C adapter needed) CAN protocols

Generic FTDI

ELM327 FTDI USB

Good option

ELM327 adapters using genuine FTDI FT232RL USB-to-serial chips. FTDI drivers are included in macOS and are very stable. Avoid fake FTDI chips — they can be permanently disabled by FTDI's driver. Buy from reputable sellers only.

Chip: ELM327 + FTDI FT232RL

Interface: USB-A (virtual COM)

Driver: Built into macOS

Price: ~£15–£35

Mac iPhone

macOS driver note: macOS includes native drivers for FTDI FT232 and Prolific PL2303 chipsets. CH340 adapters may require the WCH driver on macOS Sonoma+, though most recent versions work without it. CP210x (Silicon Labs) adapters require the Silicon Labs VCP driver. The app's USB Serial manager uses IOKit to enumerate available serial ports automatically — no manual port selection needed.

Wi-Fi adapters

TCP socket connection

Wi-Fi ELM327 adapters create their own Wi-Fi access point. Your iPhone, iPad or Mac connects to that network, and the app opens a TCP socket to the adapter's IP address (typically 192.168.0.10:35000 or 192.168.1.1:23).

OBDLink

OBDLink WiFi

Recommended

Wi-Fi version of OBDLink hardware. STN1170 chip. More reliable than generic Wi-Fi ELM327 clones. Use when BLE range is a problem.

Chip: STN1170

Default IP: 192.168.0.10

Port: 35000

Price: ~£60–£80

iPhone iPad Mac

Generic

ELM327 Wi-Fi (AP mode)

Use with care

Generic Wi-Fi ELM327 adapters vary widely in quality. Some work reliably; others have unstable TCP connections or drop frames. If using one, confirm it uses a proper ELM327 firmware (not a clone) and that the AP IP/port matches the app's Wi-Fi settings.

Chip: Varies

Default IP: 192.168.0.10

Port: 35000 / 23

Price: ~£10–£30

iPhone iPad Mac

Chipset guide

Not all ELM327 chips are equal

The ELM327 chip is made by ELM Electronics (Canada). The chip design has been widely cloned — with varying degrees of fidelity. Deep EV diagnostics require features that cheap clones often omit or implement incorrectly.

STN2120 / STN2255

OBDLink (Scantool.net)

Proprietary chips that extend ELM327 with faster CAN throughput, better multi-frame ISO-TP handling and additional AT commands. Fully backward-compatible with all ELM327 commands used by EVMetricsOBD. The best chips available in consumer adapters. All OBDLink-branded hardware uses STN chips.

Best

ELM327 v2.1

ELM Electronics

The genuine article. Full protocol support including CAN 11-bit (ATSP6), CAN 29-bit extended (ATSP7), ISO-TP multi-frame, ATCRA receive filter, ATD0 headers. Supports ATFC (flow control) needed for long UDS responses. Works well with EVMetricsOBD.

Recommended

ELM327 v1.5 (genuine)

ELM Electronics

Older genuine chip. Missing some CAN features added in v2.x. Usually adequate for standard CAN vehicles (JLR I-Pace, E-GMP, MEB) but may struggle with edge cases like Volvo/Polestar CMA 29-bit extended CAN or very long multi-frame UDS responses.

Use with caution

PIC16F627 / PIC18F2580

Counterfeit clones

Chinese clones using PIC microcontrollers with unofficial ELM327 firmware. Often advertised as "v2.1" but ship with v1.0–v1.4 equivalent firmware. Frequently fail on multi-frame ISO-TP (needed for UDS Service 22), silently drop ATSH, or return garbled responses for AT commands they do not recognise. Responsible for most compatibility complaints.

Avoid

Protocol support

What protocols do the vehicles use?

ELM327 ATSP commands select the CAN bus protocol. JLR and most modern EVs use CAN ISO 15765-4 (ATSP6). Volvo/Polestar CMA requires 29-bit extended CAN (ATSP7). Legacy vehicles may use ISO 9141 or KWP2000.

ATSP	Protocol	Speed	Used by	ELM327 v1.5
ATSP6	CAN 11-bit, 500 kbaud	500 kbps	JLR, E-GMP, MEB, Ford EV, Stellantis, most modern EVs
ATSP7	CAN 29-bit extended, 500 kbaud	500 kbps	Volvo/Polestar CMA BECM, some Renault ZE50	—
ATSPB	CAN 11-bit, 125 kbaud (J1850)	125 kbps	Body bus (TPMS, HVAC on some vehicles)
ATSP0	Auto-detect	Varies	Porsche ICE, generic OBD2
ATSP3	ISO 9141-2	10.4 kbps	Pre-2008 European vehicles
ATSP4/5	ISO 14230 KWP2000	10.4 kbps	Some 2003–2008 European vehicles

App behaviour

How the app filters adapters

The app scans for Bluetooth peripherals and sorts them by likelihood of being an OBD adapter:

Prioritised (shown at top)

· Device name contains "obd" or "odb" · Device name contains "elm" · Device name contains "carista" · Device name contains "link" · Device name contains "v-link"

Filtered out (blacklisted)

· Device name contains "Battery Monitor" (prevents 12V battery monitors from appearing in the OBD device list)