FourStroke OBD2 Elm Scanner for iPhone

At-a-glance summary

FourStroke OBD2 Elm Scanner turns your phone or tablet into a live vehicle-data monitor and diagnostics tool. It reads information from the OBD-II port and displays sensor values and trouble codes in real time, making it useful for basic troubleshooting and performance monitoring.

Required hardware

• A third-party OBD-II adapter (Wi‑Fi or Bluetooth Low Energy) is necessary to connect your device to the vehicle.
• Works with the majority of cars and light trucks worldwide, though compatibility depends on the vehicle’s OBD-II implementation.

Main functionality

• Read and clear engine fault codes with plain-language descriptions to help identify check-engine light (CEL) causes.
• Show live sensor outputs such as O2 readings, airflow, vehicle speed, coolant temperature, and engine RPM (available sensors depend on the vehicle).
• Display saved “freeze frame” data — the sensor snapshot captured when a fault occurred.
• Convert your device into an on-screen gauge cluster so you can monitor parameters without installing dedicated hardware.

Additional tools (in-app options)

• Unlock advanced sensors and telemetry via in-app purchases.
• Add measurement tools like a dynamometer for estimating horsepower and torque or a quarter-mile performance analyzer.

Important limitations and notes

• The app itself does not include the OBD-II adapter; you must supply a compatible third-party unit.
• Does not provide ABS code reading or support vehicle manufacturers’ proprietary diagnostic commands.
• Sensor availability and supported parameters vary by vehicle model and the adapter used.