4S dealership records are directly connected to the manufacturer's database, making the data hard to tamper with and the most reliable, with original parts guaranteed; third-party repair shops usually are not connected, making their data unverifiable. Therefore, we only consider the connected records from 4S dealerships as valid historical documentation.

Pure electric vehicles are classified as Class 9 Dangerous Goods due to their large lithium batteries, leading to strict shipping regulations. Shipping companies have high requirements for the loading position and fire isolation measures for dangerous goods, and some roll-on/roll-off ships refuse to accept used EVs. As a result, EVs often require more expensive special container shipping and incur additional handling fees for hazardous materials.

The technician will start the vehicle and turn on the air conditioning system, measuring the actual temperature at the vents at the lowest and highest settings with a thermometer; at the same time, they will connect a manifold pressure gauge to check if the refrigerant pressure in the high and low pressure lines is within the normal range, determining if there is a chronic refrigerant leak.