2011 E350 - AC stopped working. DTC 1437, has anyone seen this before?

[Marcianello]

The code reader says “Communication with the air conditioner has a malfunction". I dont know where to start looking, but I am guessing by the pressures that the compressor is not engaging. This happened once when a sensor was unplugged, it just refused to run the compressor. I checked everything I can think of but I have no idea what is supposed to be communicating to the AC.
Can anybody please weigh in on this and suggest something? I have searched EVERYWHERE but I cannot find an explanation for this code.
I am thinking I will have to pay a shop with a more powerful scanner than my Harbor Freight model. It does everything else just fine, but this code does not appear in any documentation I could find.