What means hardware code -3404D ?
Apple does not publish these error codes, you will have to contact an Apple Authorized Service Provider for help.
If you gave us a description of what the machine is doing then perhaps we can provide some troubleshooting steps to take. Also, when posting it helps us to know the version of OS X installed and which iMac you have.
I have a iMac 21,5" from medio 2010 3,06GHZ Intel Core i3, 12 GB with OS X El Capitan version 10.11.2
I started up to do a hardwaretest with Option - D . After a few seconds (10-15?!) my screen contained a warning "apple.com/support" and under that a code "-3403D" .
I never recieved the chance to choose a language. A ter the warning my Mac was frozen.
WHAT DOES THE (HARDWARE)CODE MEANS?
It means you need to take the machine in for service to your local Apple Authorized Service Provider. You can locate one in you area by clicking https://locate.apple.com/country
what means hardware code -3404D ?
