U007388 - TroubleshootingU007388-故障诊断

Fault code description故障码说明

DTC故障码(DTC)	Fault code description故障码描述	Possible cause of failure可能故障原因
U007388	E-CAN bus is closedE-CAN总线关闭	1.busoff1.总线busoff

Troubleshooting steps故障诊断步骤

①Power on check上电检查

1. Repower the vehicle, use the diagnostic tool to read and clear the fault codes, and check whether the fault codes and symptoms are eliminated.车辆重新上电，使用诊断仪读取并清除故障码，检查故障码及症状是否排除。 Are the test results normal?检查结果是否正常？ Yes是 Fault resolved.故障排除。 No否 Go to step 2.去步骤2。

②Check your surroundings检查周围环境

1. Check the surrounding environment for sources of magnetic fields.检查周围环境是否存在磁场源。 Are the test results normal?检查结果是否正常？ Yes是 Go to step 3.去步骤3。 No否 Drive away from the current situation.驶离当前所处环境。

③Check wiring harness and connectors检查线束及接插件

1. Power state is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”，断开蓄电池负极。 2. Check whether the ECAN communication harness is damaged or broken.检查ECAN通讯线束是否存在损坏、断裂等现象。 3. Check the ECAN communication harness connector for loose connections or damage.检查ECAN通讯线束接插件是否存在虚接、损坏等现象。 Are the test results normal?检查结果是否正常？ Yes是 Go to step 4.去步骤4。 No否 Repair or replace faulty wiring harness or connector.维修或更换故障线束或接插件。

④Check ECAN communication waveform检查ECAN通讯波形

1. Power status "OFF".电源状态“OFF”。 2. Connect the oscilloscope.连接示波器。 3. Power status "ON".电源状态“ON”。 4. Use an oscilloscope to measure the waveforms of ECAN-H and ECAN-L.用示波器测量ECAN-H和ECAN-L的波形。 Are the test results normal?检查结果是否正常？ Yes是 Go to step 5.去步骤5。 No否 Check the ECAN communication harness; if normal, go to step 5.检查ECAN通讯线束；若正常，去步骤5。

⑤Check other related systems on the ECAN communication bus检查ECAN通讯总线上其他相关系统

1. Check whether other related systems on the ECAN bus are normal.检查ECAN总线上其他相关系统是否正常。 Are the test results normal?检查结果是否正常？ Yes是 Go to step 6.去步骤6。 No否 Repair related faulty systems.维修相关故障系统。

⑥Replacing the thermal management integrated module更换热管理集成模块

1. Replace the thermal management integrated module with a new one and check whether the fault code and symptoms are eliminated.更换新的热管理集成模块，检查故障码及症状是否排除。 Are the test results normal?检查结果是否正常？ Yes是 Fault resolved.故障排除。 No否 Look for causes from other symptoms.从其他症状查找原因。   Caution:注意： ♦  After replacing the thermal management integrated module, you need to use a diagnostic instrument to recalibrate the thermal management integrated module.更换热管理集成模块后，需用诊断仪对热管理集成模块重新标定。