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	There is a fault in the CAN network and it is offlineCAN网络存在故障，离线	1.CAN bus is closed1.CAN总线关闭
		2.CAN_H and CAN-L are short circuited2.CAN_H与CAN-L短路
		3.CAN_H short circuit to ground3.CAN_H对地短路
		4.CAN-L is short-circuited to the power supply4.CAN-L对电源短路

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 the presence of magnetic fields.检查周围环境是否存在磁场。 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 Move the vehicle away from the current environment.将车辆驶离当前环境。

③General inspection一般检查

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 BCAN communication harness is damaged or broken.检查BCAN通讯线束是否存在损坏、断裂等现象。 3. Check the BCAN communication harness connector for loose connections or damage.检查BCAN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 the BCAN communication harness or connector.维修或更换BCAN通讯线束或接插件。

④Check BCAN communication waveform检查BCAN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 BCAN-H and BCAN-L.用示波器测量BCAN-H和BCAN-L的波形。 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 Check the BCAN communication harness; if normal, go to step 5.检查BCAN通讯线束；若正常，去步骤5。

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

1. Check whether other related systems on the BCAN bus are normal.检查BCAN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。

⑥Replacement of ETC on-board unit更换ETC车载单元

1. Replace with a new ETC on-board unit and check whether the fault code and symptoms are eliminated.更换新的ETC车载单元，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 ETC vehicle-mounted unit, the ETC vehicle-mounted unit needs to be recalibrated with a diagnostic instrument.更换ETC车载单元后，需用诊断仪对ETC车载单元重新标定。