State of Health (SOH) tells you how much of the original battery capacity remains. Here's how to use it. Reading the report: SOH is usually shown as a percentage of original capacity. A car at 90% SOH retains roughly 90% of its original range. Also check for cell imbalance (voltage spread between modules)—a low SOH with balanced cells is often fine, but high imbalance causes sudden range drops and charging problems. Acceptable thresholds: for a car under 3 years old, expect 90%+ SOH. For 3-5 years, 85-90% is normal. Below 80% SOH, the battery may soon need replacement—replacement costs can exceed the car's value, so negotiate hard or walk away. How to verify: don't trust a screenshot. Ask for a live screen recording of the diagnostic app (like the brand's official tool) starting from the car's VIN page. Cross-check the fast-charging curve: a healthy battery charges at near-peak rate up to 60-70%; a degraded one tapers early. Finally, remember that hot climates degrade batteries faster—if the car spent its life in southern China, scrutinize SOH more carefully.

An OBD scan is one of the most cost-effective tools in a remote pre-purchase inspection, but you need to know what it can and cannot tell you. What it reveals well: current and stored fault codes across the engine, transmission, ABS, airbag, and body modules. A car with dozens of cleared codes in multiple modules may have electrical problems or a history of tampering. It also shows readiness monitors — if all monitors show 「not ready」 on a car that claims to be freshly serviced, the codes were probably cleared recently to hide something. What it reveals with the right software: live data. You can watch engine idle stability, coolant temperature under load, transmission shift behavior, and battery cell voltages on EVs. Abnormal fuel trims or misfire counters can flag worn injectors or coils before any warning light appears. What it cannot do: prove real mileage (odometers can be corrected digitally), detect physical accident repairs, or judge paint and rust. Practical advice: ask your inspector for a full-system scan report with screenshots, not just a 「no codes」 verbal summary. For Chinese brands, make sure the tool supports their protocols — mainstream scanners cover BYD, Geely, and Chery well, but some small brands need brand-specific software.

The lifespan of rubber sealing strips for frameless doors is usually only 4-5 years. We carefully press the sealing strip at the edge of the roof to check for loss of elasticity and use a high-pressure water gun to wash the seams of the windows to check for direct water leakage due to aging.