Usage of Apple Hardware Test and Apple Diagnostics on Mac?

How to Launch and Use Apple's Built-in Hardware Diagnostic Tools, Such as Apple Hardware Test and Apple Diagnostics?

Apple has added a built-in diagnostic tool that checks all computer components and displays results and recommendations about how to solve any existing issues to their Macs.

With this tool, you can check hard disk drive failures, memory faults, and video graphic card (GPU) and processor (CPU) performance. You can also check the entire motherboard and additional modules, such as network and Bluetooth adapters. Even fan operations can be scanned for possible errors.

The diagnostic tool can help if you are experiencing issues that software solutions could not fix. This is achieved by scanning the entire computer, both hardware, and software. Knowing the source of the problem enables you to apply a solution. This article describes how to launch the Apple Hardware Test and Apple Diagnostics programs on a Mac computer.

Table of Contents:

• Introduction
• Launch built-in diagnostic tool on Mac
• Most common error codes of the Apple Hardware Test report
• Error codes displayed within Apple Diagnostics report

Launch built-in diagnostic tool on Mac

The method to launch Apple Hardware Test and Apple Diagnostics is identical on all Mac computers, whether it is a desktop version, such as iMac, Mac mini, or Mac Pro, or portable versions, such as MacBook, MacBook Pro, or MacBook Air.

1. To launch the diagnostic tool on your computer, begin with connecting it to a power source.
2. Next, disconnect all peripherals, such as external drives, multiple monitors, speakers, etc. - the keyboard, mouse, and main display can stay connected.
3. Once you are ready, shut down the computer and turn it back on while holding down the D key. Keep holding until you see a progress bar or language selection. If you are launching the Apple Hardware Test, you will see a pixelated Apple logo. While booting Apple Diagnostics, you may see a simple progress bar or language selection window.
4. If you have launched Apple Hardware Test, enable the check box next to 'Perform extended testing' and click the Test button. On Apple Diagnostics, allow Checking your Mac to run and complete.
5. Once the tool finishes scanning the computer, it will display a report detailing any issues found. If you run Apple Diagnostics, an error code with other information about the existing issue will be displayed.
6. Otherwise, the report will state that no issues were found and that this will be software-related if you are still having problems. In this case, the easiest way to solve the existing situation would be to backup your operating system or perform a complete reinstall of Mac OS.

If you have problems launching the diagnostic tool following this method, hold down Option and D while starting the Mac. This will boot the diagnostic tool from the internet rather than the computer hard disk. Bear in mind, however, that without proper internet access, this method will not work.

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Most common error codes by Apple Hardware Test report

If the tool could locate issues with Mac hardware, the report will display an error code relating to specific hardware. To find the best solution, make a note of the code or take a picture with your mobile device. The list below shows codes often displayed by the Apple Hardware Test tool.

List of error codes and related hardware:

• 4AIR - AirPort wireless card
• 4ETH - Ethernet
• 4HDD -  Hard disk (includes SSD)
• 4IRP -  Logic board
• 4MEM - Memory module (RAM)
• 4MHD - External disk
• 4MLB - Logic board controller
• 4MOT - Fans
• 4PRC - Processor
• 4SNS - Failed sensor
• 4YDC - Video/Graphics card

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Error codes displayed within Apple Diagnostics report

Apple Diagnostics has different error codes, but some report similar hardware issues. The table below displays all error codes and descriptions published by Apple.

Issue description	Error code
Issues were not found.	ADP000
Issues related to Wi-Fi hardware	CNW001, CNW003, CNW004, CNW005, CNW006
Wi-Fi network was not detected, no available networks detected, or hardware is not working	CNW007, CNW008
Issues related to the built-in camera	NDC001, NDC003, NDC004, NDC005, NDC006
USB hardware related issues	NDD001
Keyboard related issues	NDK001, NDK003, NDK004
Issues related to Bluetooth hardware	NDL001
Trackpad related issues	NDR001, NDR003, NDR004
Issues related to Thunderbolt hardware	NDT001, NDT002, NDT003, NDT004, NDT005, NDT006
Unable to detect a serial number	NNN001
System Management Controller (SMC) related issues	PFM001,PFM002, PFM003, PFM004, PFM005, PFM006, PFM007
Computer's firmware related issues	PFR001
Fan related issues	PPF001, PPF003, PPF004
Issues related to the memory module	PPM001
Issues related to onboard memory	PPM002, PPM003, PPM004, PPM005, PPM006, PPM007, PPM008, PPM009, PPM010, PM011, PPM012, PPM013, PPM014, PPM015
Power adapter related issues	PPP001, PPP002, PPP003
Unable to test the power adapter	PPP007
Issues related to processor (CPU)	PPR001
Unable to detect battery	PPT001
It is recommended to replace the battery, because it is functioning normally but holds less charge.	PPT002, PPT003
The battery needs to be serviced	PPT004, PPT006
The battery was not installed properly	PPT005
Replace battery	PPT007
Issues related to SD card reader	VDC001, VDC003, VDC004, VDC005, VDC006, VDC007
Issues related to the storage device	VDH002, VDH004
Inaccessible macOS Recovery mode	VDH005
Issues related to display	VFD001, VFD002, VFD003, VFD004, VFD005, VFD007
Graphics processor (GPU) related issues	VFD006
Audio hardware related issues	VFF001

 

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