We use two steps: 1. Insert a medical-grade endoscope through the spark plug hole to visually inspect cylinder wall scratches and carbon buildup on the piston top; 2. Extract an engine oil sample to check for large metal debris or emulsification (caused by coolant leakage).

Once the car system (especially in a closed ecosystem) undergoes a major version upgrade, its bootloader is usually locked, preventing downgrades. If this happens, there is basically no solution in an overseas environment. Therefore, we strongly warn: do not blindly insert a USB drive to upgrade while offline.

Vehicles sold domestically in China only have the "Environmental Information List" and the "Vehicle Qualification Certificate," which are not the COC of the European system. We will provide a notarized English translation of the Chinese qualification certificate. If local customs strictly require the original European COC, the vehicle will not be able to clear customs.