We will use a megohmmeter (insulation resistance tester) to measure the insulation resistance of the high-voltage bus. If the resistance value is below the national safety standard, it indicates a risk of leakage, and the vehicle will be deemed unqualified.

Handling claims with an overseas exporter works best when expectations are set before payment. Prevention: put the inspection standard, photo/video evidence requirements, and a dispute clause into the sales contract. Keep all chat records and payment receipts. Typical process if issues arise: 1) Notify the exporter within 48-72 hours of delivery with photos/videos as evidence. 2) Most disputes fall into two buckets: shipping damage (handled via marine insurance — this is why insurance matters) or undisclosed mechanical defects (handled per contract, often via partial refund, spare parts, or repair cost sharing). Realistic expectations: exporters rarely accept returns, so negotiate compensation instead. A reputable company will usually cover reasonable repair costs for defects confirmed to pre-exist shipment. Tip: for higher-value cars, hire a local third-party inspection at destination as final evidence — it strengthens any claim significantly.

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.