Request a live video call during the test drive rather than a pre-recorded one. Cold start first: listen for rattling or metal scraping in the first seconds — possible timing chain or hydraulic lifter issues. During acceleration, a whining from the gearbox area can mean bearing wear; hesitation or jerking in an automatic suggests transmission problems. Braking: the pedal should feel firm, not spongy, and the car must not pull to one side. Turn the wheel fully in both directions and listen for clicking — a classic CV joint fault. Insist on a highway segment too: vibrations above 100 km/h often point to unbalanced wheels or bent rims. Ask the driver to film the dashboard throughout — warning lights that flicker on briefly are still faults that OBD will record.

A professional pre-purchase inspection in China normally covers five parts: exterior and interior condition, a lift inspection of the chassis and frame, engine bay checks, a road test, and OBD diagnostics. Prioritize the chassis rails and A/B/C pillars for cut-and-weld repairs, engine oil leaks and timing noises, transmission shift quality, and OBD fault codes — cleared codes leave telltale history data. For EVs, add battery pack casing, insulation values, and battery state of health (SOH). Insist on original timestamped photos with the VIN visible and a written conclusion such as 'fit for export' or 'major defects found.' A report that only says 'good condition' is not worth paying for.

Obtaining precise internal resistance at different SOC levels requires disassembling the battery pack and connecting it to a professional charge-discharge cabinet for several days of cycling tests. This is beyond the scope of non-destructive used car inspections; we only provide real-time estimated internal resistance data based on OBD port readings.