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.

Heavy-use vehicles often look clean in photos but show specific wear patterns. Here's what to check: 1. Rear sag and suspension: ask for a side-profile photo of the car on level ground. If the rear sits noticeably lower than the front, the rear springs or shocks may be worn from constant heavy loads. Compare with factory ride height specs. 2. Pedal and seat wear: accelerator and brake pedals with polished metal patches, and a driver's seat bolster that is flattened or cracked, indicate high mileage or intensive commercial use — even if the odometer says otherwise. 3. Hitch and tow bar marks: check the rear bumper area in close-up photos for scratches, bolt holes, or a removed tow bar mount. Ask the seller directly whether the car ever towed. 4. Underbody and frame: request underbody photos. Look for bent or scraped crossmembers, fresh undercoating hiding damage, or uneven tire wear across the rear axle. 5. Data check: many ride-hailing cars in China have records in maintenance databases — a professional inspection agency can flag cars with commercial fleet history. If the seller refuses underbody or close-up photos, treat it as a warning sign and consider another vehicle.

Many car owners do not have their first maintenance done at authorized dealerships, leading to gaps in early data. In such cases, we do not blindly trust the odometer; instead, we analyze the tire production dates and wear levels, as well as the depth of grooves on the brake disc edges, using the "gold standard" of physical wear to infer the intensity of early use.