On page 58 of the service manual, Dell lists these instructions:
This diagnostic is the new on-board diagnostic tool and replaces the ePSA 3.0 diagnostics. It has a clean and modern user interface, quicker tests, simplified messaging.
SupportAssist | On-board Diagnostics can be initiated by one of the following methods:
- Pressing F12 to enter one-time Boot Menu and selecting Diagnostics to initiate the diagnostics OR Fn+Power
- BIOS POST detecting a hardware failure or error and initiating the diagnostics
The SupportAssist | On-board Diagnostics is embedded with the BIOS and is launched by the BIOS internally. The embedded system diagnostics provides a set of options for particular devices or device groups allowing you to:
- Run tests in either Quick Test Mode or Advanced Test Mode
- Run thorough tests to introduce additional test options to provide extra information about the failed device(s)
- Run tests in either Automatic Mode or Interactive Test Mode
- Run interactive tests on LCD panel and keyboard
- Display or save test results
- View status messages that indicate if the tests are completed successfully
- View error messages that indicate if problems were encountered during the test
NOTE: Some tests for specific devices require user interaction. Ensure that you are present at the computer terminal when the diagnostic tests are performed.
For more information, see SupportAssist Pre-Boot System Performance Check.
This appears to be built into the motherboard, much in the same way Apple has done it for their systems. No partitions to accidentally delete 👍🏻