Chosen Solution
Hi I have the above error in diagnostics. It appears to point to LCD Temperature Sensor. I have tested another LCD with my Mac and it isn’t the LCD itself. This results in fans running at full speed as well as LCD Proximity reading as - in istat menu app. Any help would be appreciated Thank you
The error TLOp points to: ‘‘Excessive LCD panel area temperature, Verify that the DisplayPort cable is securely connected to both the LCD panel and the logic board. This is straight out of the Apple manual. I would say since you tried a second display and it too showed the error that points to the LVDS connector on the logic board its self the contact within it has a problem, the solder joint of the connector or the rest of the sensor logic within the logic board needs to be investigated.
I would first check that the the LCD thermal sensor cable connector is correctly in place. See step #8 of this guide: iMac Intel 21.5" EMC 2428 Display Replacement
