Occassional problem-Reefer won't begin cooling again after defrost?

We have about 10 2013 Carrier reefers in our fleet, they are either X4 7300 or 7500. Every once in a while they will do this:

After a defrost cycle, the unit will not cool at all, ie, you go into the sensors for supply air temp and it will not even begin producing cold air. Its as if its just recycling whatever is in the box. Engine will keep running until it throws a code for either "computer error" or "microprocessor error", I don't remember which. But after a certain amount of time it will shut down and throw that code, sometimes along with "box temp out of range".

I'm not sure if the code has ever cleared on its own and restarted, but I know if I catch it and shut the whole unit off for a few minutes, let everything clear, and restart, it will work just fine like nothing ever happened. Anyone ever encounter this problem?

I am thinking that maybe a solenoid or valve somewhere is sticking, because the unit doesn't ice up, it simply produces no cold air until you shut it off and restart it.

 

Older? They are barely two years old

 

Its not icing up, I said it does this after it finishes the defrost cycle. It simply won't start to cool again. Shut the unit, restart it, it will run just fine.

 

Carrier shops are beginning to become nearly as incompetent as the new breed of truck drivers. Rather than actually pinpoint and fix the problem, they would rather try their luck at replacing major components like compressors. Occasionally, there are a few good ol boys at a carrier Thermo King shop that know their stuff. But that is very rare today

 

The ones we got 2 years ago would not shut off in colder weather if you left them on stop/start. Not sure if carrier ever fixed that issue either, but any time the temp outside got below about 15 degrees...the command to #### off the unit when it reached the setpoint would not go through because the engone coola temp was not warm enough. That may be a good thing to keep the fuel from waxing and gelling, but overall that wastes a lot of fuel if the weather stays above 0 degrees.