When and How to Run Hardware Diagnostics

As much as I would like to say that Apple's hardware is flawless, that simply isn't true. The fact is, Apple sources a lot of their internal components from companies like Intel, NVidia, and many others. Those components are then shipped to manufacturers like Foxconn in China to assemble. In some cases, the hardware used in a high-end MacBook Pro is the same component used in a mid-range HP EliteBook. Neither are 100% immune to hardware failure or issues. When these failures occur, it could result in catastrophic failure. At least those problems are easy to identify and resolve. The tougher challenge is when a less catastrophic problem arises. These can be tricky to identify.

Every Mac comes with a hardware diagnostic tool to help identify possible hardware failure. This diagnostic utility checks everything from memory to the video card to the system board and much more. There are two types of diagnostic tests you can choose to run : a short test (which takes about 5 - 10 minutes to run) and a long test (which can take an hour or longer in some cases, depending on your hardware configuration). As you can imagine, the long test is more thorough.

There are three different ways to initiate a hardware diagnostic test, depending on the age and type of the hardware you have: 

If you have a new Mac (mid-2013 or later), use Apple Diagnostics (built into your Mac)

  1. Disconnect all external devices except the keyboard, mouse, display, and speakers. If you have an Ethernet cable or external DVD drive, disconnect it.
  2. Restart your Mac, holding down the D key while the Mac restarts.
  3. After your Mac restarts, Apple Diagnostics starts automatically. When Apple Diagnostics is finished, it lists any problems it finds. (The reference code is for use by Apple Support.)
  4. Follow the onscreen instructions. To start your Mac from the built-in recovery disk and open the β€œContact Apple Support” webpage in Safari, click β€œGet started.”
  5. If Apple Diagnostics reports that your Wi-Fi card is not working properly, contact Apple Support or take your Mac to an Apple Store or Apple service provider.

If your Mac has OS X 10.8.3 or earlier, use Apple Hardware Test (built into your Mac)

  1. Disconnect all external devices except the keyboard, mouse, display, and speakers. If you have an Ethernet cable or external DVD drive, disconnect it.
  2. Restart your Mac, holding down the D key while the Mac restarts.
  3. After your Mac restarts, you should see the Apple Hardware Test chooser screen. If you don’t, Apple Hardware Test may not be available on your Mac. You may be able to start Apple Hardware Test from the Internet. Reconnect your Mac to the network, then restart your Mac while holding down both the Option and D keys.
  4. When the Apple Hardware Test chooser screen appears, select the language you want to use, then press the Return key or click the right arrow button.
  5. When the Apple Hardware Test main screen appears (after about 45 seconds), follow the onscreen instructions.

If you updated your Mac to OS X 10.8.4 or later, use the system software disc or USB flash drive that came with your Mac

If your Mac came with a system software disc or USB flash drive, you may be able to use it to start Apple Hardware Test.

Important: Follow these instructions only if your Mac came with a system software disc or USB flash drive. Do not try to use a disc or USB flash drive from another Mac model.

  1. Disconnect all external devices except the keyboard, mouse, display, and speakers. If you have an Ethernet cable or external DVD drive, disconnect it.
  2. Insert the system software disc or USB flash drive.
  3. Restart your Mac, holding down the D key while the Mac restarts.
  4. When the Apple Hardware Test chooser screen appears, select the language you want to use, then press the Return key or click the right arrow button.
  5. When the Apple Hardware Test main screen appears (after about 45 seconds), follow the onscreen instructions.

If Apple Hardware Test detects a problem, it displays an error. Make a note of the error before you call Apple Support for a replacement. If you are able to start your Mac using OS X, you can retrieve the error and send the information to Apple, using the System Information utility (Apple menu > About This Mac, then click More Info).

Posted on August 4, 2015 and filed under How To, Mac.