We use two steps: 1. Insert a medical-grade endoscope through the spark plug hole to visually inspect cylinder wall scratches and carbon buildup on the piston top; 2. Extract an engine oil sample to check for large metal debris or emulsification (caused by coolant leakage).

We will proactively provide a third-party inspection report (such as from Check Doctor), support customers in re-inspection at the store, and promise "return of major accident vehicles."

Testing is mandatory. Troubleshooting electrical devices in the car is part of the standard procedure. We will test the window lift motors, mirror folding, air conditioning compressor and fan, electric seat tracks, etc. Any stuttering or failure of electronic components will be recorded.