Apple 2009 iMac - Page 22

iMac (21.5-inch, Late 2009) — General Troubleshooting 22
2010-11-18
AHT Error code Suspected part and
Location
Suggested Action Notes
4SNS/1/40000000:
TC0H
CPU temp sensor
(located on back side
of logic board). Note:
this sensor is not
available as a separate
service part
Check CPU sensor cable
connection to logic board.
It requires removal of the
logic board.
If the sensor is
disconnected, the
CPU fan will run
at full speed.
4SNS/1/40000000:
TG0H
GPU temp sensor
(located on back side
of logic board)
Check GPU sensor cable
connection to logic board.
It requires removal of the
logic board.
If sensor is
disconnected the
CPU fan will run
at full speed.
4MOT/4/40000002:
ODD-xxx
Optical fan/blower Verify that the ODD
blower/fan cable is securely
connected to the right side
of the logic board and that
there are no obstructions
that would prevent the
blower/fan from rotating.
Replace fan if the error
continues.
Normal fan
operation, except
the ODD blower.
4MOT/4/40000002:
HDD-xxx
Hard drive fan/blower,
located below logic
board, near hard drive
Verify that the HDD
blower/fan cable is securely
connected to the top of the
logic board and that there
are no obstructions that
would prevent the blower/
fan from rotating. Replace
fan if the error continues.
Normal fan
operation, except
the HDD blower.
4MOT/4/40000002:
CPU-xxx
CPU fan/blower,
located next to left
speaker (logic board
has to be removed to
replace CPU blower)
Verify that the CPUblower/
fan cable is securely
connected to the left side
of the logic board and that
there are no obstructions
that would prevent the
blower/fan from rotating.
Replace fan if the error
continues.
Normal fan
operation, except
the CPU blower.
Note: Make sure
black mylar tape
along the bottom
of LCD panel is
not obstructing
fan blades, if so,
cut tape and re-
stick to LCD.