One of the changes Apple has made with the 2013 MacBook Airs is new hardware testing. Apple has moved on from Apple Hardware Test with its vintage Mac OS 9-like look to the new and more automated Apple Diagnostics. As with Internet Apple Hardware Test, Internet Apple Diagnostics can also be run via Apple’s cloud services. See below the jump for the details.
Running Internet Apple Diagnostics on a mid-2013 Mac or later
To use Internet Apple Diagnostics, start up your Mac and hold down both the Option and D keys on your keyboard.
You should see a gray screen with an animated globe appear. It should say something like “Starting Internet Recovery. This may take a while” Depending on your connection speed, it may also switch to a countdown clock to show you how long until it’s fully booted.
Once the boot process has completed, you’ll be asked to select your language.
Once you’ve select a language, Apple Diagnostics will begin and a “Checking your Mac” screen will appear in that language. While the diagnostic runs, a progress bar will indicate the estimated time remaining.
Your test results will appear after testing finishes. If no problems were detected, a “No issues found” message will appear. If issues were discovered, a brief description of the issues will be displayed along with additional instructions and error reference codes.
To exit Internet Apple Diagnostics, click the Restart or Shut Down buttons at the bottom of the screen.