Your boiler is currently cooling itself down after finishing a heating or hot water cycle, which is a normal operating state rather than a permanent failure.

pump / fan overrun

What causes this fault?

This occurs because the boiler needs to dissipate residual heat from the internal heat exchanger after it has finished heating your home or water. The pump and fan continue to run for a few minutes to ensure the unit cools down safely and prevents internal components from overheating. It is a protective measure rather than a breakdown.