Diagnosis
The temperature sensor (NTC thermistor) is reading an abnormally high temperature in the cooking chamber during the low-power Keep Warm cycle.
How to Fix It
This is often a false reading caused by residual heat. Cancel the error, let the appliance cool to room temperature completely (about 60 minutes). Unplug it for 2 minutes, then plug it back in and try the Keep Warm function again with an empty basket.
If That Didn't Work
The NTC thermistor, located near the heating element, may have a faulty connection or be out of specification. This requires disassembly to test and replace the sensor.
Heads Up
Do not use Keep Warm for more than 30 minutes as stated in the guidelines. Extended use in this low-heat mode can trigger this sensor error as components heat unevenly.