I have an Early 2011 MacBook Pro. When I hold down D immediately after restart, it boots to the normal login screen.
When I hold down ALT+D (with a working wifi connection before the reboot) the same thing happens.
I'm running macOS 10.13.5
I don't have an original Applications Install disc 2 as mentioned here.
Any ideas why I can't enter AHT mode? I'm trying to troubleshoot an intermittent fault where the mac won't boot, gives me 3 beeps on a black screen (suspect faulty RAM, but want to run AHT first to check).
Recovery mode works correctly, but doesn't give the option to enter AHT mode.