GLC300 2019 X253 Low RPM when climate below 27oc

[Quang Pham]

Hi all,

I have a problem on GLC2019 X253. When the climate cold below 27oC the RPM decrease from 750-800 to 600. My car is in warranty time and the dealer told me it cannot fix, Mercedes Vietnam Told the same, they cannot fix the issue. Pls help me to find out what happen so i can fix it.
My car has been replace thermostat, ECU, Outside Air sensor