1. Check the contents of the trunk: Confirm whether there are any movable or unsecured items inside the trunk, such as tools, spare tires, luggage, etc., which may produce abnormal noise due to vibration during vehicle operation.
2. Check the trunk lock buckle and hinge: Check whether the trunk lock buckle is tightened, and whether the hinge between the trunk cover and the body is loose or worn. Loose or damaged components may cause gaps in the trunk when closed, resulting in abnormal noise.
3. Check the sound insulation and sealing strip of the trunk: Check whether the sound insulation materials inside and around the trunk are intact, and whether the trunk sealing strip is aging or falling off. Damage to sound insulation materials or unsealed sealing strips may cause external noise to enter the car, or amplify the sound when the internal parts of the trunk vibrate.