The short answer

An iPhone can display supported OBD-II diagnostic information when an app connects to a compatible adapter plugged into the vehicle. The phone alone cannot read the car’s diagnostic port. Louro can help explain the codes the scan reports.

If you searched for a check-engine light app, the first decision is hardware compatibility. ‘Bluetooth’ on a product box is not enough: the adapter, iPhone app and vehicle must work together. Check Louro’s current scanner guidance before buying an adapter.

What you need before a scan

Use a compatible iPhone with Louro installed, a supported Bluetooth OBD-II adapter and a vehicle that exposes the diagnostic information you want. Follow the adapter manufacturer’s instructions. Different Bluetooth implementations and vehicles support different functions; an iOS-compatible adapter is not a promise of every manufacturer-specific module.

  • Check Louro’s published scanner compatibility guidance.
  • Park safely before connecting hardware or using the app.
  • Find the diagnostic port using the vehicle’s documentation.
  • Follow the adapter’s connection and ignition instructions.

A diagnostic code is a starting point

A stored code tells you what the onboard system detected; it does not identify a replacement part with certainty. Keep the full code, when it appeared and any symptoms. A technician may need additional tests to distinguish several possible causes.

A flashing check-engine light can indicate an urgent problem. Follow the owner’s manual and arrange professional help when needed. Do not keep driving simply because an app description sounds reassuring. Avoid clearing codes just to make the light disappear: it can remove useful diagnostic context without fixing the cause.

No adapter yet? Start with the information you already have

If a shop or another scanner has already supplied a code, you can ask Opie about that code without performing a fresh hardware scan. Include the exact vehicle, symptoms and the original reading. A code explanation and a physical OBD-II scan are different tasks.

Put it into practice

How to do this in Louro

  1. Review Louro’s scanner page, connect compatible hardware as instructed and open Louro while parked.
  2. Open your car’s scan tool in Garage and run Scan Vehicle with the supported adapter connected.
  3. Review the reported codes and supported readings. Keep the result with the correct vehicle.
  4. Ask Opie to explain the result and help prepare questions for a qualified technician; confirm the diagnosis before replacing parts.
A question you can ask Opie

Explain this code for my vehicle. What does it describe, what information is still missing, and what should I ask a technician to check?

Louro does not replace professional diagnosis or repair. Diagnostic coverage varies by vehicle and adapter. Cockpit live gauges require supported hardware and Garage+ according to the current App Store description.

Bring the record with you.

Louro connects your vehicle information in one Garage. Start with your car and build from there.

Download Louro for iPhone

iPhone · iOS 26.2+ · Free download with optional in-app purchases.

Sources and product information

Published by Opaius, the company behind Louro. General guidance and app workflows should be checked against your vehicle’s documentation and the current app version.