err: TEMP FALL ERROR

For some reason I cannot account for, I am getting this error on the LCD screen (I'm using the RepRap XXL lcd controller).
err: TEMP FALL ERROR

I have grepped for this error in the robo3d firmware source code, and it does not appear anywhere. I have searched for "FALL" and it does not appear anywhere.

Any ideas?

I think it should be fail error. That happens when the thermistor drops below an acceptable error usually indicating the wire has come lose and is no longer reading correctly. Usually the threshold is below 5C but it might fail out at a very high temperature reading as well.