The mileage is about 50 thousand km, with the Toyoda Kamimizu 4AR hybrid powered by the 4AR engine in 2013. Users reflect: the car suddenly lost power in the driving, the vehicle can not drive, multi-functional display display "please check the hybrid power system," battery charging warning light light, vehicles stop by the roadside waiting for rescue. Inspection and analysis: the maintenance personnel arrived at the scene for preliminary inspection and confirmed that the scene could not remove the trouble, and the vehicle was towed back to the shop for repair. Refer to the history of vehicle maintenance, vehicle maintenance on time, no collision accident maintenance record. Verify the fault phenomenon is consistent with the user, open the ignition switch, "READY" indicator light 1s extinguished, read the fault code is "P0A08 - DC/DC converter state circuit", fault code can not be cleared. According to the analysis of the maintenance manual, the possible causes are as follows: fuse, wire harness or connector, inverter pump assembly, inverter cooling system, inverter assembly, power control unit and drive bridge assembly. The maintenance personnel carry out the following inspection. Check that the DC/DC IGC fuse of engine room No. 2 relay box is not abnormal. Check the IGCT MAIN fuse of engine room No. 2 relay box. Check that the DC/DC-S fuse of engine compartment relay box and junction box assembly is not abnormal. Check the engine control unit connector is not abnormal. Check the inverter assembly connector with the converter. Check the DC/DC fuse in fuse box. Remove the inverter top cover and measure the insulation resistance of the inverter with multimeter. Check that the voltage of the AMD terminal is the same as that of the auxiliary battery, comply with the regulations, check the AMD connection line and install it properly. Measuring the inverter "A13-3" and the body voltage are the same as the auxiliary battery voltage. Measuring the inverter "A13-1" and the body voltage are the same as the auxiliary battery voltage. 11 measuring the inverter "Al 3-5" and the body resistance of 130 ohms, meet the requirements. 12 the auxiliary battery in the luggage compartment is 11.2 V, the specified voltage is 13.01 ~ 15 V, and a 12 V battery is connected in parallel, and the vehicle can start to drive, but the fault light is still lit. Troubleshooting: replace the inverter assembly according to the instructions of the maintenance manual. All the tests are normal and troubleshooting. Review summary: the steps to repair the hybrid power car are still to check in the factory, ask the user, check the fault, check the fault code, read the data flow, make the plan, check the measurement, repair the accessories, replace the parts and test the test. The maintenance personnel must be specially trained by the hybrid electric vehicle, and the power battery of the hybrid motor vehicle is high voltage, and the safety operation regulations for electric shock must be strictly implemented.