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.

We thoroughly rule them out by checking if the cabin wiring harness is melted, if the seat belts have water stains or mold, if there is unusual rust or debris in the seat tracks and cigarette lighter, and by verifying with the insurance company for any "total loss claims." These two types of cars are an absolute sales ban for us.

We will never perform blind deep disassembly unless there are clear severe fault codes or extreme noises. The sealing of the engine and transmission is crucial, and compromising the factory seals to investigate non-existent issues is unprofessional. We rely on data flow and external acoustic and fluid analysis to make judgments.