Live engine readings
RPM, speed, coolant temp, battery voltage, engine load, throttle, fuel level and more — streaming in real time as you drive.
Connect. Diagnose. Drive.
Read your car's live data and fault codes in the browser or mobile app
Pair a Bluetooth LE OBD2 adapter, watch engine data stream in real time, and see exactly what your check engine or ABS light is trying to tell you — in plain English, with likely causes and what to check first.
Coming soon onApp Store
Coming soon onGoogle Play
What it does
A full scan tool, without the scan tool
Plain-English fault codes
Every check engine and ABS code comes with what it means, whether you can keep driving, likely causes and what to check first.
Unknown codes still explained
Manufacturer-specific codes get decoded by system and severity instead of leaving you with a bare number.
Freeze frame and trends
See the exact conditions when a fault was set, plus rolling engine and vehicle speed graphs.
Emissions readiness
Catalyst, EGR, evaporative and O2 heater monitors at a glance — know before you drive to the test station.
Track and drift mode
Session timer, live g-force, lateral and longitudinal load, lap times and drift scores.
Your garage
Keep multiple cars with photos and specs, each with its own saved setup.
Saved drive history
Every session and run kept for each car, so you can look back at how it behaved.
Custom dashboards
Arrange the gauges you actually care about and save the layout per car.
Synced everywhere
Your cars, sessions and layouts follow you between phone and computer.
Full demo mode
Five simulated scenarios — healthy car, check engine, ABS fault, both at once, and an unrecognised code.
Nothing to install
It runs in the browser. Open the page, pair the adapter, start reading.
Inside the app
See it running
Warning lights up top, then every stored and pending code broken down in language you can act on.
Six live gauges plus throttle, intake temp, mass air flow, manifold pressure, fuel level and runtime.
Speed, revs and a live g-force circle with a session timer for lap and drift runs.
Adapter compatibility
Browsers can only talk to Bluetooth Low Energy adapters — Vgate iCar Pro BLE, LELink, vLinker and similar. The cheap Bluetooth Classic ELM327 dongles are invisible to every browser. Use Chrome or Edge on desktop or Android; iOS Safari has no Web Bluetooth support. Demo mode works in every browser.
See compatible adapters & laptops →Plans
Scanning is free, always
Scanning and code explanations are free, always. Pro keeps your cars, sessions and layouts saved to your account.
Free
$0
- Live engine readings and gauges
- Check engine and ABS light codes
- Plain-English code explanations
- Demo mode
Pro
Everything in Free, plus:
- Your garage with multiple cars, photos and specs
- Saved drive history for every car
- Lap times and drift scores kept forever
- Custom dashboard saved per car
- Everything synced across phone and computer
Monthly$4.99per monthYearlyBest value$29.99per yearHalf the price of monthlyLifetime$60one timePay once, keep it
Sign in on c4link.app to choose a plan. Got a C4 LINK code? Redeem it there to unlock Pro for free.
Plug in and find out what's wrong
No install, no account needed to scan. Try it with the simulated adapter first.
Coming soon onApp Store
Coming soon onGoogle Play