Hi,
During the period in the "yellow" zone do you know if the compressor and evaporator fan were running?
Looking at the sequence in the "green" zone it appears normal with the peaks being the times when the auto defrost cycle is occurring (approx every 10 hours?).
During the defrost cycle, the compressor and evap fan are both turned off and the temperature is allowed to rise to melt any accumulated ice off from the evaporator unit. The defrost heater is also turned on to speed up the process. The defrost thermostat will signal if the temp near the evaporator unit gets too high and the heater will be turned off if this happens before the end of the defrost cycle. At the end of the defrost cycle the control board turns the compressor and evap fan back on again to drive the temp back down to the normal set operating temp.
What should happen at the end of the defrost cycle is that the compressor and evap fan will now cycle on and off maintaining the temp within the set limits, until the next defrost cycle occurs.
How long they stay on for to reach the correct operating temp depends on factors such as how long and often the door has been left open due to normal usage i.e. how much cold air has been lost or warmer air entered if you like, how much warmer food was placed in the compartment during the time which needs to be frozen and the ambient temp in which the freezer is working. The compressor will turn off when the lower set limit temp has been reached and then turn on again when the temp rises above the set upper limit.
This can be seen in the green zone by the temp varying between the set operating limits between the defrost cycles.
It does seem that the temp is rather cold, as I thought that the normal operating temp would be 0°F and not hovering around -10°F. Although the operating range seems to be between -12°F to 2°F which I suppose is reasonable
If you have the mini manual (tech sheet, you said that you ran the diagnostics so I was hoping that you had it) it should show the set temp ranges on that. The part # is GE 31-51954-2 but I can't find it online so I'm not sure what the set lower- upper range limit is. If you haven't got it check in the back of the cabinet in the compressor area somewhere as GE refrigerators/freezers used to have the tech sheet placed there in a plastic folder.
Where it goes astray in the yellow zone before you selected turbo freeze and also in the red zone, it seems like it was being reset after a defrost cycle had ended and that it works properly in driving the temp back down again but then fails to maintain it there.
If the compressor and evap fan are stopped when the temperature is above say 2°- 5°F during a normal cycle and if the temp sensor is accurate regarding the temp then perhaps there's a problem with the control board not starting the compressor and fan if this is what's happening but it seems that it is starting the compressor and fan OK at the end of the defrost cycle.
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