The typical cause of this code is a connection issue. There are two common places:
-The fan connector itself as they typically need to be replaced at the same time the fan is due to either corrosion or the plug being head damaged and melted.
-Battery/Chassis Grounds having loose or corroded connection. The negative battery cable has a large lead that is grounded to the engine itself and then there is a smaller lead that is grounded to the core support. Check and clean both of these.
If neither of these fixes the issue, you'll be looking for damaged wiring harness or a faulty CCRM or PCM.