Using Apple Hardware Test
If you suspect a problem with the MacBook Pro hardware, you can use the Apple
Hardware Test application to help determine if there’s a problem with one of the
computer’s components, such as the memory or processor.
To use Apple Hardware Test:
Disconnect all external devices from your computer except the power adapter.
If you have an Ethernet cable connected, disconnect it.
Restart your computer and hold down the D key as it starts up.
When the Apple Hardware Test chooser screen appears, select the language for
Press the Return key or click the right arrow button.
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 code. Make a note of
the error code before pursuing support options. If Apple Hardware Test doesn’t detect
a hardware failure, the problem might be software related.
Problem, Meet Solution