Hi...Need some help to avoid future trouble.

We have a GE Cafe Side by Side. It's been fine since new until this morning when I noticed a new sound coming from it. I heard what may have been the refrigerant cooling system turn on, last for 3 seconds and turn off again. It did this repeatedly every 90 seconds or so. I opened the freezer and things were melting. The in-door thermometers were at 29F for the freezer and 43F for the fridge. They were set to and usually maintain 0F and 37F. All fans and lights seemed to be ok.

At this point with not much to do and thinking hung microprocessor, I shut off the AC breaker going to the unit and turned it back on after 20 seconds. The unit powered back up, fans and lights working. In about one minute, the same sound of what I called the refrigerant system turning on in the paragraph above happened but this time whatever is engaged at that point stayed on! The unit has been dropping temperature since. It's 90 minutes later now and the unit is at 20F and 40F per the in-door thermometers.

Is something broken or about to break? If so, a costly repair? Is there anything I can check or clean? Did it just need a simple reboot! We have no service contract on this unit. Only 4 years old at max. The fridge cost was around $2k! I have not performed any cleaning (other than interior) or service since new. I have repaired fridges before and am somewhat handy. I have a volt meter and basic electrical/mechanical know-how.

Any insight is much appreciated. Thank you, Jim.