RANGER Apple Device Support · chapter 18 of 18
Month 9: Hardware checkup
In this chapter Objectives 7.4, 7.6
Objective 7.4
Finding hardware issues with Apple Diagnostics
Running the test
Apple Diagnostics (formerly Apple Hardware Test) checks hardware such as memory, the logic board and wireless modules. Prepare: update macOS if you can, shut down, disconnect everything except keyboard, mouse, display, Ethernet and power, put the Mac on a hard, ventilated surface. On Apple silicon: hold the power button until Options appears, release, then press and hold Command-D.
- Results show reference codes; ADP000 = no issues found
- Command-R reruns, R restarts, S shuts down, Command-G (Get started) shows service options
Exam tip A confirmed hardware failure goes to your organization's repair process, with the reference code.
Check yourself 1Before running Apple Diagnostics on a Mac, what should you disconnect?
- Nothing; leave every accessory connected
- The power adapter
- All external devices except keyboard, mouse, display, Ethernet and power
- The keyboard and mouse, so that nobody can interrupt the test while it runs
Show the answer
Answer: C. All external devices except keyboard, mouse, display, Ethernet and power
Apple's preparation: install updates if you can, shut down, disconnect all external devices except keyboard, mouse, display, Ethernet (if used) and AC power, and put the Mac on a hard, flat, ventilated surface.
Check yourself 2Apple Diagnostics finishes with the reference code ADP000. What does it mean?
- The memory has failed
- No issues were found
- The test couldn't run
- The battery needs service
Show the answer
Answer: B. No issues were found
ADP000 means no issues found. Other reference codes point to possible problems, for example with Wi-Fi, Bluetooth or USB hardware; give the code to the service provider.
Objective 7.6
Finding accessory issues with a system report
Is the accessory even there?
Open System Report (System Settings > General > About > System Report, or Option + Apple menu > System Information). Check the section for the connection: USB, Thunderbolt/USB4, Bluetooth. If the accessory isn't listed, check the cable, port, hub and its power. If it is listed but doesn't work, look at drivers, the app or setup.
Exam tip File > Send to Apple shares the report with AppleCare during a support call.
Mac laptops ask first
On Mac laptops with Apple silicon, a new USB or Thunderbolt accessory or SD card triggers an alert to allow it. Don't Allow means the Mac won't recognize it or give it data access, though it can still charge. Reconnect to be asked again, or change Privacy & Security > Accessories. A locked Mac must be unlocked first.
Rosa: I clicked Don't Allow on the drive. Oops.
You: Unplug it, plug it in, click Allow. Fixed.
Check yourself 3A Bluetooth barcode scanner won't pair with a Mac. Which System Report section shows the Mac's Bluetooth hardware and connected devices?
- Network > Wi-Fi
- Software > Extensions
- Hardware > Power
- Hardware > Bluetooth
Show the answer
Answer: D. Hardware > Bluetooth
System Report lists hardware installed in or connected to the Mac. For a Bluetooth accessory, check the Bluetooth section for the controller and connected or paired devices.
Check yourself 4A USB scanner doesn't work on a MacBook Pro with Apple silicon. It isn't listed in System Report's USB section, and it works on other Macs. Nobody saw an accessory alert. What should you check?
- The printer driver for the scanner
- The cable, port and any hub
- The scanner's app settings
- Apple Account sign-in
Show the answer
Answer: B. The cable, port and any hub
If System Report doesn't list the accessory, the Mac doesn't detect it, so check the physical path: cable, port, hub and power. If it were listed, you'd look at software.
Go deeper
More on the objectives in this chapter, in the same exam-ready detail.
Objective 7.4 · Identify Mac hardware issues using Apple Diagnostics.
Apple Diagnostics
Run it, read the code
Disconnect everything except keyboard, mouse, display, Ethernet and power. On Apple silicon: hold the power button until Options appears, release, then hold Command-D. Results show reference codes (ADP000 = no issues). Command-R reruns, Command-G shows service options. Escalate confirmed failures through the organization's repair process with the code.
Objective 7.6 · Identify accessory connection issues using a system report on Mac.
Accessories in System Report
Listed or not?
In System Report, check USB, Thunderbolt/USB4 or Bluetooth. Not listed: cable, port, hub, power. Listed but not working: driver, app or setup. Mac laptops with Apple silicon ask to allow new accessories; Don't Allow blocks data (charging still works). Change it in Privacy & Security > Accessories.
Practice questions
Answer in your head, then open the answer. Ranger’s Device Doctor has 653 questions like these for Apple Device Support, with mock exams.
Question 1A technician suspects a hardware fault on a MacBook Pro with Apple silicon. How does he start Apple Diagnostics?
- Turn the Mac on and immediately hold D
- Start up in macOS Recovery and open Disk Utility First Aid
- Turn the Mac on and hold Option-D
- Hold power until Options appears, then Command-D
Show the answer
Answer: D. Hold power until Options appears, then Command-D
On Apple silicon, press and hold the power button until Options appears, release, then press and hold Command-D. Holding D or Option-D at startup is the Intel-based Mac method.
Question 2A USB barcode scanner works on other Macs but not on the receiving Mac. System Report shows the exhibit with the scanner plugged in. What does this suggest?
- A privacy setting is blocking the scanner from reaching the app
- The scanner's app needs Full Disk Access
- The Mac's firewall is blocking the scanner
- The Mac doesn't detect it; check cable, port, hub, scanner
Show the answer
Answer: D. The Mac doesn't detect it; check cable, port, hub, scanner
If a device is missing from Hardware > USB, macOS isn't detecting it at the hardware level, so test the cable, port, any hub and the device itself before blaming software.
Question 3You suspect a hardware fault on a Mac with Apple silicon, but System Report looks normal. Which built-in test checks the hardware and gives reference codes?
- Wireless Diagnostics, opened from the Wi-Fi status menu
- Disk Utility First Aid, run on every volume
- Activity Monitor's Spotlight Diagnostics
- Apple Diagnostics, from startup options with Command-D
Show the answer
Answer: D. Apple Diagnostics, from startup options with Command-D
Apple Diagnostics tests the Mac's hardware and shows reference codes. On Apple silicon, hold the power button to open startup options, then press Command-D.
Question 4What is Apple Diagnostics mainly used for?
- To repair a damaged startup disk
- To find which app or background process is using the most CPU and memory
- To reinstall macOS when the Mac won't start
- To find a failing hardware part, such as memory or the logic board
Show the answer
Answer: D. To find a failing hardware part, such as memory or the logic board
Apple Diagnostics checks hardware such as memory, the logic board and wireless modules, so you can tell hardware problems from software ones and recommend the right repair.
Question 5Apple Diagnostics shows a reference code that points to a possible hardware issue on a company Mac. What should the help desk tech do next?
- Escalate using the organization's repair process, with the reference code
- Reinstall macOS from macOS Recovery and run the test again to clear the code
- Reset NVRAM and rerun the test until the code is gone
- Erase the Mac with Erase Assistant
Show the answer
Answer: A. Escalate using the organization's repair process, with the reference code
If Apple Diagnostics confirms a hardware failure, escalate to determine your organization's repair options (Apple, an authorized provider or self-service repair), and provide the reference code.
Apple, iPhone, iPad and Mac are trademarks of Apple Inc. Ranger Gamez is not affiliated with or endorsed by Apple. The practice questions are written to the published exam objectives; they are not real exam questions.