Asus TS500-E6/PS4 - Manual (Page 69)

ASUS TS500-E6/PS4 4-17
4.4 Internal LEDs
1. Standby Power LED
The motherboard comes with a standby power LED. The green LED lights up
to indicate that the system is ON, in sleep mode, or in soft-off mode. This is a
reminder that you should shut down the system and unplug the power cable
before removing or plugging in any motherboard component. The illustration
below shows the location of the onboard LED.
2. CPU warning LED (ERR_CPU1, ERR_CPU2)
The CPU warning LEDs light up to indicate that an impending failure of the
corresponding CPU.
The warning LEDs function only when you install the ASUS ASMB4.