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).

We will remove the chassis guard to physically inspect the battery pack's lower shell for serious dents or scratches, and check for signs of mud or sand intrusion in the waterproof vent at the edge of the battery pack.

For dealers who purchase the same brand models in bulk over a long term, we can coordinate senior technicians domestically to offer paid, regular Zoom video technical Q&A to resolve the issues you encounter locally.