Sleep Mode; Hibernation Mode; Symptom-To-Fru Index - ThinkPad T480s Hardware Maintenance Manual

Sleep mode

When the computer enters sleep mode, the following events occur:
• The LCD is powered off.
• The solid-state drive is powered off.
• The microprocessor stops.
To put your computer into sleep mode, press Fn+4.
To return to normal operation, press the Fn key only.
In certain circumstances, the computer goes into sleep mode automatically:
• After a period of inactivity specified in power plan settings
• When the battery power is low

Hibernation mode

In hibernation mode, the following occurs:
• The system status, RAM, VRAM, and setup data are stored on the solid-state drive.
• The system is powered off.
Note: If the computer enters the hibernation mode while it is docked to the docking station or the port
replicator, do not undock it before resuming normal operation. If you do undock it and then try to resume
normal operation, you will get an error message, and you will have to restart the system.
If you have defined one of the following actions as the event that causes the system to go into hibernation
mode, perform that action.
• Closing the lid.
• Pressing the power button.
Also, the computer goes into hibernation mode automatically after a period of inactivity specified in power
plan settings.
When the power is turned on, the computer returns from hibernation mode and resumes operation. The
hibernation file in the boot record on the solid-state drive is read, and system status is restored from the
solid-state drive.

Symptom-to-FRU index

This section contains following information:
• "Numeric error codes" on page 36
• "Error messages" on page 37
• "Beep symptoms" on page 38
• "No-beep symptoms" on page 39
• "LCD-related symptoms" on page 39
• "Intermittent problems" on page 40
• "Undetermined problems" on page 40
The symptom-to-FRU index in this section lists symptoms and errors and their possible causes. The most
likely cause is listed first, in boldface type.
Note: Do the FRU replacement or other actions in the sequence shown in the column headed "FRU or
action, in sequence." If replacing a FRU does not solve the problem, put the original part back in the
computer. Do not replace a nondefective FRU.
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Chapter 4 Related service information