Thought this might help -
My air con was not performing very well sometimes changing to warm then back to cool, showed no codes and the engine revs would change when I engaged it so the ecu was responding.
The air pump relay (engine box - relay 8) was dropping out on its own say-so ! changed relay and now everything normal, including me !
with all the hot and cold going on ..... I thought it might be an age thing !

 

Good find and correction to your A/C debacle.