BYD Song-DM car multimedia black screen

A new generation of BYD Song-DM models, customers came to the store to report that the multimedia screen suddenly went black during normal driving, and the combination instrument displayed “Please check the multi-function frequency controller”.
There are four possible reasons for the analysis: 1. PAD assembly failure. 2. Multi-function frequency controller failure. 3. System control failure. 4. Line failure, etc.
Troubleshooting:

1. Use VDS to read system related faults, and find that the multi-function frequency controller and multimedia power supply systems cannot scan in and out;
2. Long press the multimedia power button to try to restart without effect. Disconnect the negative pole of the battery for 10 minutes and then reinstall and restart. The multimedia is still black; check that there are no other accessories installed on the vehicle. 3. Check the relevant fuses of the instrument distribution box and find that the F2/36 fuse is blown. After replacing the new fuse, it immediately blows again. This indicates that there is a local short circuit fault in the circuit that the fuse is responsible for;
3. By consulting relevant information, the F2/36 fuse supplies power to the PAD rotating motor, the multi-function frequency controller, and the panoramic image integration module respectively. It is suspected that a module or line has a short circuit. The circuit transmission diagram is as follows:
4. According to the circuit diagram, use the elimination method to unplug the three modules of the PAD rotating motor, the multi-function frequency controller, and the panoramic image integration module one by one for testing. After unplugging the panoramic image integration module, it is found that the F2/36 fuse is no longer blown. While unplugging these modules, the ground resistance of the power supply line corresponding to the module is measured. There is no abnormality, indicating that there is no short circuit to the ground in the line. It is suspected that the short circuit is caused by an internal fault in the panoramic image integration module. 6. Switch the panoramic image integration module, and the test run fault still exists!
5. The downstream of the panoramic image integration module supplies power to the PAD and USB assemblies respectively. After disconnecting the PAD assembly connector, the fault still exists. Disconnect the USB assembly module, and the F2/36 fuse is no longer blown.
6. Replace the USB assembly module and the fault is eliminated.