Lenovo ThinkCentre M75n, Hardware Maintenance Manual, Page: 42 / 120

POST error codes
Each time you turn on the system, it performs a series of tests that check the operation of the system and
some options. This series of tests are called the
Power-On Self-Test , or POST . POST checks the following
operations:
• Some basic system-board operations
• Memory operation
• Video operation
• Whether the boot drive is working
If the POST detects a problem, an error message appears on the screen. A single problem might cause
several error messages to appear. When you correct the cause of the first error message, the other error
messages probably will not appear on the screen the next time.
Error code
POST error message Description/Action
0135 CPU fan failure
System fan failure
Power fan failure
Front fan failure
Rear fan failure
Auxiliary fan failure
ODD fan failure
This error message is displayed
when a fan fails and the system
might be overheating.
Press F10 to exit.
0211 Keyboard not found
This error message is displayed
when no keyboard is detected.
0164 Memory configuration change has
occurred
This error message is displayed
when the memory size is
changed.
Press F10 to exit.
1762 Storage device configuration change
has occurred
This error message is displayed
when a hard disk drive change or
an optical drive change has been
made.
Press F10 to exit.
1820 More than one external fingerprint
reader is attached. Turn off and
remove all but the reader that you set
up within your main operating
system.
This error message is displayed
when more than one external
fingerprint reader is connected to
the computer.
Turn off and remove all but the
reader that you set up within your
main operating system.
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ThinkCentre M75nHardware Maintenance Manual