Apple Diagnostics: The Hidden Trick to Check Your Mac

By Anna | Posted to Home > Wiki, on September 24th, 2021

Summary: This article concludes what Apple Diagnostics is and how to use Apple hardware diagnostics. Common diagnostic codes related to hardware issues are also covered.

Apple Diagnostics on Mac

Mac models since June 2013 are fitted with the Apple Diagnostics feature. When you think your Mac has a hardware problem, Apple Diagnostics is capable of helping you find which hardware component might be faulty. Today I’m going to talk about what Apple Diagnostics test is and how to use it.

What is the Apple Diagnostics test?

Apple Diagnostics, also known as Apple Hardware Test, is a special booting mode on MacBooks to locate where the problematic hardware component is. Diagnostic Mode on Mac helps check the hardware issues of the logic board, RAM, battery, and wireless components of Mac.

Besides, older Mac models before June 2013 run a similar program called Apple Hardware Test (AHT). The AHT works similar to Apple Diagnostics, and it should give you the same information you need to fix your hardware issues.

How do you start Apple Diagnostics?

Booting your Mac into Apple Diagnostics is quite simple, but you need to prepare well before starting it. And the way to run Apple Diagnostics on the M1 Mac is a bit different from an Intel-based Mac.

Prepare your Mac:

  • Turn off your Mac.
  • Disconnect all peripheral devices except for the keyboard, mouse, ethernet connection (if you have one), and the power connection.
  • Turn off the Mac firmware password if you’ve set one.
  • Make sure your Mac is on a hard flat surface with good ventilation.

Start Apple Diagnostics for Intel processor:

  • Press the power button and immediately hold the D key as your Mac boots up.
  • Release the key when asked to choose the language.
  • Select the language using arrow keys

Run Apple Diagnostics for Apple Silicon:

  • Release it as soon as you see the startup Options window.
  • Press and hold Command + D on your keyboard.
  • Select I agree when prompted.

Then a progress bar shall appear and once the test completes, you’ll get a report on your Mac screen with one or more diagnostics codes. You can write them down or take a picture of them as these codes can help you identify the accurate hardware problems. If you can't resolve the issues on your own, take your Mac to an Apple Store or Apple Authorized Service Provider for help.

Apple Diagnostics
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Note: If you want to repeat the test, just click “Run the test again” or press the Command + R keys.

How to exit Apple Diagnostics?

Now, choose one of the instructions mentioned below to quit Apple Diagnostics:

  1. Click Shut Down or press and hold the S key to shut down your Mac.
  2. Select Restart or press and hold the R key to restart your Mac.
  3. Click Get Started. Your Mac will restart to a webpage with more information. When you've finished, choose Restart or Shut Down from the Apple menu.
Apple Diagnostics result
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Common Apple Diagnostics codes

As aforementioned, you’ll see one or more reference codes in a report after the Apple Diagnostics finishes. The codes point specifically to a particular error. And below you can find diagnostic reference codes related to some of the common issues on Mac.

ADP000: No hardware issues.
CNW001-CNW006: Problems related to Wi-Fi.
NDL001: Issue with the Bluetooth hardware.
PFM001-PFM007: SMC issue.
PFR001: Mac firmware issue.
PPT001-PPT007: Problems related to the battery.

For more information about reference codes, you can visit the Apple Diagnostics reference codes support page.

FAQs about Apple hardware diagnostics

How long does an Apple Diagnostic take?

Normally the Diagnose Mode on Mac will take 2 or 3 minutes and shall provide you with a “No issues found” message or a list of issues with respective codes after setting the language.

Apple hardware diagnostics not working, how to fix?

If you’re sure to have met the requirements for launching Apple Diagnostics, then try to press and hold Option + D keys at startup to use Apple Diagnostics over the internet.

Does Apple Store do free hardware diagnostics?

Running Apple Diagnostics on your Mac is free and you only have to pay when your Mac needs repair.

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