Temp Sensor, change it.
If your pump cost $500 it wasn't the circ pump, it was the primary pump.
---- is a message called "watch dog" and is a temperature related issue. Your sensor is breaking down. If it was the circ pump, you would be getting a "Flo" message.
I would suggest calling the dealer and having him fix it. If you wish, purchase a temp sensor and figure it out, but remember, things we try ourselves are not always done "right", sometimes costing more.