Dell G3 3590 SELEK_N18E_MB error 2000-0314

[titomno2]

Hi,
I have a Dell G3 3590 ( SELEK_N18E_MB 18812-1) and the Nvidia GPU is permanently deactivated following error 2000-0314.
Basically it say the thermistro GPU is out of value (cold start It ready 120°C permanently).
I need help to understand what piece of hardware may have failed and how to replace it as everyhting was working fine and the thermal paste was removed and replaced by PTM7950 properly.
All schematics are available on the forum and if someone could be able to help me and give me direction on what component to check first.
I found THM261 on the back of the board but can't understand how it can have the GPU information properly.
Thanks
Best regards,

[titomno2]

Some more information.
Looking temperature with HWinfo64 the temperature sensor n°4 is completely fuzzy going from 2°C to 188°C.
At 2°C fan RPM is set at 0 (no rotation).
At 188°C fan RPM is set at 4000rpm (full speed for both fans).
Here after is the strange dent of the sensor 4 like some sort of capacitor discharge and a repetitive waveform:

For the moment visual inspection did not show me any defective part, and i'm stuck to find if the thermistor is an NTC or something else.
The schematic are not very usefull as nothing is given information for the GPU (found only CPU Thermal schematic).

If any of you is familiar with such protective device, it will be very helpful. Changing the complete motherboard is a bit of a shame as it could be just a tiny component failing.
So for the moment the laptop is working without the GPU (deactivated by bios right at start (cold or warm)) and the behavior of the fan is really annoying.
I checked with thermal camera and not hot point found.


Thank you, any advice will be greatly appreciated as I'm turning around the rabbit hole.

[titomno2]

Still looking for parts that may enter in the sensor 4 for this measurement:

Not sure if it is the right parts but I want to look at the R7957 and R7956 as these resistor are near the GPU and 10K make me think to some sort of NTC.

Can someone tell me what is a 10KR2J-L-GP I found a lot of it on many schematic but can't find any datasheet.