Malfunction pump of the cooling circuit. You don't feel any vibrations when touching the pump after activating the “Refill mode” via the Communicator software.

1. Check the electrical resistance of the pump winding. Replace the pump if infinite.

2. Drain the liquid cooling circuit, open the pump and check if the pump rotor is not blocked. If so, remove the rotor and clean the bearings of the pump. See service manual chapter "Cleaning the cooling pump".

Malfunction Fan Control board

Replace the Fan Control board. See "Removing a board in the card cage".

Pump end of life.

Replace the pump. See "Replacement of the pump motor and rotor" or "Replacement of the complete cooling pump".