I have a Dell XPS 13 9350 model with the latest BIOS & GPU drivers that I downloaded directly from dell's website, lately I have noticed that the fan is not spinning when I turned on the laptop until some minutes later "until the laptop reach a critical temperature " and the the fan would run at maximum speed and the laptop will shut down I replaced the thermal paste but this would only delay the problem, I preform the a bios diagnosis and nothing is not normal even when fan check starts the fan would start for the test and then it will stop, today I was unable to start my laptop, Everytime I turn it on the fan would spin at maximum speed and the laptop will shutdown after less than a minute I did a BIOS diagnosis and finally I get an error about the thermal sensor as shown in the attached picture, would you kindly help me to resolve this problem . Thanks in advance .
Fun pass diagnosis check without problems , my problem is with the ambient thermistor it's not signaling to the fan in order to start before reaching critical temperature .
The thermistor is usually part of the fan assembly. Hopefully that's the one that failed - and if so it's an easy, inexpensive replacement. If the problem persists after the fan assembly is replaced, one of the other sensors likely failed - meaning the mainboard would need to be replaced. Since the fan is a $30 part, while the mainboard can be 10X that or more, start with the fan assembly.