Heater Support Pump Dry Running

This code has come up a couple times now. I haven’t had the system flushed so I don’t see how any air pockets could be in the system. I went ahead and made sure the reservoir was full( it was at the min mark last time). Last time we had issues with the ac/heater the repair shop said they had to “reprogram” the control unit. They also re charged the ac and it’s been fine for two years. Makes me wonder if it needs it again.
It’s a 2015 Sportwagen TDI.