It is a Mercedes GLC 260 4Matic 2018, engine 274 920. CGDI CG100X will correct mileage for this model. Mercedes CAN Filter is required.
1. Confirm car model, year and VIN
2. Record original km, the current mileage is 125682KM. Better take a screenshot. 
Old mileage KM
3. Remove dashboard and check chip type
Kilometers are stored in the chip: R7F701414
4. Run CG100X software --> Dashboard --> choose series --> Brand-->Model-->Year/chip
6. Input new mileage you desired and start change mileage.
7. Install CAN Filter to cluster.
8. Check if mileage has been corrected.
