Thanks for the answer.
Can you show the output of $ sudo dmesg | grep thermal ?
Mine is:
[ 0.430394] thermal_sys: Registered thermal governor 'fair_share'
[ 0.430394] thermal_sys: Registered thermal governor 'bang_bang'
[ 0.430394] thermal_sys: Registered thermal governor 'step_wise'
[ 0.430394] thermal_sys: Registered thermal governor 'user_space'
[ 0.430394] thermal_sys: Registered thermal governor 'power_allocator'
[ 2.652159] thermal LNXTHERM:00: registered as thermal_zone0
[ 2.652160] ACPI: thermal: Thermal Zone [TZ10] (17 C)
[ 2.652230] thermal LNXTHERM:01: registered as thermal_zone1
[ 2.652231] ACPI: thermal: Thermal Zone [PCT0] (17 C)
[ 2.652295] thermal LNXTHERM:02: registered as thermal_zone2
[ 2.652296] ACPI: thermal: Thermal Zone [UAD0] (17 C)
But why Thermal Zone shows the default value 17 °C that is too small. 