Apple MD094LL/A manual Diagnostics, Sensors Errors, Suggested Action

Diagnostics

The following diagnostics are required for this product:

•Apple Service Diagnostic (ASD), version 3S140

•For iMac (27-inch, Mid 2010): Apple Hardware Test (AHT), version 3A202

•Bluetooth Service Diagnostic (BSD) 1.1

Sensors Errors

Run latest available service utilities to determine if any thermal sensors or blowers are malfunctioning. When a test reports an error, reseat appropriate connections and check that all air flows are free from obstruction. If issue persists, replace the corresponding part (sensor, blower, logic board, video card, or power supply). See chart below for correlation between affected sensor, sensor location, and additional checks to perform.

Note: AHT can be run by pressing the D key on startup (if hard drive was not reformatted, or if adequate system specific restore DVD is inserted). If a sensor error is detected, AHT will report an error code containing the affected sensor name (ex:“4SNS/1/40000000 TC0H” error code reports to sensor TC0H).

Sensor	Suspected part and Location	Suggested Action	Notes
TA0P	Excessive incoming Ambient air	Verify that incoming/outgoing air vents	All fans ramp at full
	temperature, or Ambient temp	are free from obstruction , that sensor	speed if sensor is
	sensor damaged/disconnected	cable is securely connected to the top	disconnected.
	from logic board.	edge of the logic board and attached to
		the left speaker housing. Replace sensor
		cable if damaged.
T00p	Excessive Optical Drive area	Verify sensor cable is securely connected	The ODD fan will run
	temperature, or ODD temp	to the logic board and the sensor	at full speed if sensor is
	sensor damaged/ disconnected	is properly attached to the ODD	disconnected.
	from logic board.	mechanism. Replace sensor cable if
		damaged.
TH00	Excessive Hard Drive area	Verify sensor cable is securely connected	The HD fan may run at
	temperature, or HDD temp	to top left side of logic board and it’s	full speed if the sensor
	sensor damaged/disconnected	connected to hard drive. Check for	is disconnected.
	from logic board. Use the	damaged cable on logic board.
	correct sensor cable, each drive
	vendor has a unique sensor
	cable model.
Tm0p	Excessive logic board	Test with known-good logic board
	temperature (this sensor is part
	of logic board)
TL0p	Excessive LCD panel area	Verify that the LCD sensor cable is	The CPU fan will run at
	temperature, or LCD temp	securely connected to the logic board	full speed if the sensor
	sensor damaged/disconnected	and the sensor is attached to the LCD.	is disconnected.
	from top of logic board	Replace the sensor cable if damaged

2010-09-09 iMac (27-inch, Mid 2010) — General Troubleshooting 25