What is the EV and HEV mode switching of BYD Qin?
1 Answers
BYD Qin EV automatically switches to HEV mode, and the vehicle cannot be charged. Cause analysis: On-board charger, circuit battery pack, DC-DC, PTC, electric air conditioning pump, wiring harness failure. Troubleshooting process: Use the VDS diagnostic tool to read the information of each module. Only the battery management system reports the P1A3400 pre-charge failure fault. The data stream shows the current total voltage of the battery pack is 444V, the minimum single-cell battery voltage is 3.464V, and the maximum single-cell battery voltage is 3.485V. The pre-charge status is not pre-charged. The high-voltage distribution box of this vehicle is built inside the power battery pack. According to the circuit diagram, disconnect the low-voltage connector B28 of the power battery pack and measure the voltage of pin 4 (pre-charge contactor power supply) as 12.86V. It is preliminarily ruled out that the pre-charge failure fault is caused by the low-voltage circuit.