After an iPhone repair, you naturally want to make sure that all components and functions are working correctly. A new display, a replaced battery, or a repaired camera may seem to work properly at first glance, but that doesn’t always mean everything is technically functioning as it should.

Prefer to see how Apple Diagnostics works in practice? Watch our video and discover how to check different components and what messages such as Genuine, Used, and Unknown mean.

What is Apple Diagnostics?

Apple Diagnostics is a built-in diagnostic tool from Apple for Macs and iPhones. It allows you to check a device’s internal hardware for potential issues and identify faulty components, such as the battery or the logic board.

On a Mac, Apple Diagnostics is accessed through a specific startup procedure. On an iPhone, you can start the diagnostic environment by using a specific button combination while connecting the device to a power source.

Why is Apple Diagnostics useful for repair technicians?

When carrying out a repair, simply replacing a component is not enough. You also want to check whether the device functions properly after the repair.

For example, suppose you have replaced a display. At first glance, the screen may appear to work correctly, while there could still be issues with certain touch points. The same applies to a camera repair, where the camera may open but not function properly.

Want to learn more about the benefits of Apple Diagnostics within the repair process? Read our blog ‘The Importance of Apple Diagnostics for iPhone Repair Technicians’.

For repair technicians, Apple Diagnostics can help with:

• Identifying hardware issues.
• Checking functions before a repair.
• Checking the device after a repair.
• Investigating issues with a replaced component.
• Checking whether additional steps are required to complete a repair.

How do you start Apple Diagnostics on an iPhone?

You can start Apple Diagnostics on an iPhone by following these steps:

• Turn off the iPhone.
• Press and hold the volume up and volume down buttons at the same time.
• Connect the iPhone to a power adapter, preferably 18 W or higher. You can also connect the iPhone to a powered-on computer that is connected to mains power.
• Release the volume buttons as soon as the Apple logo appears.
• Apple Diagnostics will now start.
• Follow the on-screen instructions.
• Select ‘Diagnostics or Repair’ and then choose ‘Start Diagnostics’ to run the test.

Please note: the available diagnostic options and exact procedure may vary depending on the iPhone model and software version. Therefore, always check Apple’s latest instructions for the device you are working on.

Would you like to see the full process explained in more detail, step by step? Read our guide ‘Apple Diagnostics on iPhone: Step-by-Step Hardware Test’.

Which tests can you run with Apple Diagnostics?

• Mobile Resource Inspector (MRI): Checks the overall functionality of the device and its various components (1–2 minutes). A green check mark means that no issues have been detected. An exclamation mark indicates that an issue has been found.
• Audio for Self Service Repair: Tests all speakers.
• Display Pixel Anomalies: Checks the display for abnormal or defective pixels.
• Multi-Touch: Tests whether the screen responds correctly to multiple simultaneous touch inputs.
• Face ID: Tests the Face ID sensors and dot projector, which projects invisible infrared dots onto the face to map its facial structure for Face ID.
• Camera Image Quality: Tests the image quality of all cameras.

After Apple Diagnostics: Calibrating a Component

After replacing certain components, you may need to complete the repair and calibrate the component. You can do this through the iPhone’s Parts and Service History.

Please note: Before you begin, make sure you have a stable Wi-Fi connection and that the battery level is above 20%.

Follow these steps:

• Turn on the iPhone.
• Go to Settings → General → About → Parts and Service History.
• The component that needs to be calibrated will be displayed.
• Select ‘Restart & Finish Repair’.
• The iPhone will restart and Repair Assistant will appear.
• Select a Wi-Fi network. The iPhone will then begin configuring and calibrating the component.
• Once the process is complete, select ‘Restart’.
• After the iPhone restarts, return to Parts and Service History to check the status of the component.

Watchour YouTube video for more information about the Apple Diagnostics process on an iPhone.

What Do the Results After Calibration Mean?

After calibrating a component, you can check the Parts and Service History to see how the iPhone recognizes the component. You may encounter several different statuses:

• Used: A genuine Apple part that was previously used in another device.
• Genuine: A genuine Apple part that has been correctly installed and configured.
• Unknown: iOS is unable to verify the installed component. For a display, common causes include a non-genuine display or calibration issues.

If the calibration is completed successfully, the battery section will display the battery health and charge cycle count.

What if the Calibration Fails?

If Repair Assistant is unable to complete the calibration, first check a few practical things and then try the calibration process again.

Check whether:

• The iPhone has a stable internet connection.
• The battery level is above 20%.
• The battery and other replaced components are installed correctly.
• The issue is still present after restarting the iPhone.
• The calibration works if you try again after approximately 15 minutes. A temporary outage or reduced availability of Apple services may sometimes prevent Repair Assistant from completing the calibration.

If necessary, restart the iPhone and try the calibration process again.

Error Messages

Message: Not Calibratable

The ‘Not Calibratable’ message means that the component is not functioning as expected and therefore cannot be calibrated. The iPhone can still be used as normal.

Message: Locked Part

The ‘Locked Part’ message means that Activation Lock for the component is linked to someone else’s Apple Account.

FAQ

What is Apple Diagnostics on an iPhone?

Apple Diagnostics is a diagnostic tool that allows you to check supported iPhones for various hardware issues and functions.

The available tests depend on factors such as the device model and the diagnostic environment being used.

What Does Genuine Mean for an iPhone Part?

Genuine means that a genuine Apple part has been correctly installed and configured.

What Does Used Mean for an iPhone Part?

Used means that the part is a genuine Apple part that has previously been used or installed in another iPhone.

What Does Unknown Mean for an iPhone Part?

Unknown means that iOS is unable to verify the part. For a display, common causes include a non-genuine display or calibration issues.

Do You Need an Internet Connection for Repair Assistant?

Yes. To complete a repair using Repair Assistant, the iPhone must be connected to the internet. Apple also states that the battery level must be above 20% and that the device must be running up-to-date software.

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