U10 code appears and the cooker does not build pressure or switches to keep warm prematurely.

Safety first: Unplug the cooker and allow it to cool and depressurize before opening the lid.

Seal and valve checks:

• Inspect the silicone lid gasket for cracks, hardening, or deformation. Replace if not perfectly round and flexible.
• Ensure the gasket is seated evenly in its groove all around the lid.
• Check that the steam release valve is set to the correct 'Seal' or pressure position according to the model.
• Clean the float valve and ensure it moves freely and seals properly with its silicone cap.

Test again with water only. Persistent U10 usually indicates a sealing issue or, less commonly, a faulty pressure sensor.