How to resolve the restricted function issue in BYD Song EV?
2 Answers
During an actual vehicle test, after starting the vehicle, the dashboard displayed an "EV function restricted" fault, making it impossible to switch to EV mode. The fault was confirmed, and the electronic fan was operating at high speed. By checking the data stream, it was found that the IPM radiator temperature was 35 degrees, while the motor temperature was 155 degrees, indicating an excessive (abnormal) temperature difference. Analysis suggests a fault in the drive motor cooling system.
A couple of days ago, I worked on a Song EV that also displayed a 'function restricted' warning. The technician used a computer to read the fault code, which showed an excessive battery voltage difference. In this case, there's an 80% chance the battery module is faulty. The 4S shop will disassemble the battery pack for balance calibration or replace the faulty module. Owners should never try to fix this themselves, especially avoid randomly unplugging high-voltage connectors! My advice is to pull over immediately if you see this warning on the road, try restarting, and if that doesn't work, call for a tow truck. In daily use, avoid leaving the car parked with a low battery for extended periods, and stop using fast charging immediately if the gun abnormally disconnects. These details can help reduce the battery failure rate.
