Full Diagnostics for Apple laptops

Apple provides built-in hardware diagnostic tests that run outside of the Operating System. This is a quick suite of tests to determine if any obvious hardware failures have occurred within the machine.

If more in-dept diagnostics need to be run, the machine needs to run the full Apple Service Diagnostics (ASD) and can only be performed at an Apple store or IS&T Hardware Services in the Atlas Service Center.

How to run the built-in Apple Hardware Diagnostics:

1. Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable), and connection to AC power.
2. Make sure that your Mac is on a hard, flat, stable surface with good ventilation.
3. Shut down your Mac.
4. Turn on your Mac, then immediately press and hold the D key on your keyboard. Keep holding until you see a screen asking you to choose your language. When Apple Diagnostics knows your language, it displays a progress bar indicating that it's checking your Mac:

Checking your Mac takes 2 or 3 minutes. If any issues are found, Apple Diagnostics suggests solutions and provides reference codes. Note the reference codes before continuing.