Testing is mandatory. Troubleshooting electrical devices in the car is part of the standard procedure. We will test the window lift motors, mirror folding, air conditioning compressor and fan, electric seat tracks, etc. Any stuttering or failure of electronic components will be recorded.

Many connected features are tied to the car's original market. Start with the basics: the infotainment language, navigation maps and voice assistant may only support Chinese, and some systems require a local SIM or account that cannot be transferred to overseas owners. For driver-assistance systems, check whether the model relies on hardware that works without Chinese map data. Lane keeping and adaptive cruise usually work abroad, but map-dependent features like highway pilot may not. Ask the seller to test each key function on video before shipment: boot-up, touchscreen response, app connectivity and over-the-air update status. Also confirm the battery management system and motor controllers have no region locks. Get written confirmation that the features you are paying for are functional in your destination country, and keep that document with the purchase contract.

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).