U125087 - TroubleshootingU125087-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
U125087	There is a fault in the communication between MCU and GW_ACU_DMS_1_A (0x387), and the message is lostMCU与GW_ACU_DMS_1_A(0x387)通信存在故障，报文丢失	1. The communication link is disconnected1.通信链路断开

Troubleshooting steps故障诊断步骤

①General inspection一般检查

1. Check whether the ACANFD communication harness is damaged or broken.检查ACANFD通讯线束是否存在损坏、断裂等现象。 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 whether there is any loose connection or damage to the wiring harness connector.检查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 2.去步骤2。 No否 Repair or replace the faulty communication harness.维修或更换故障通讯线束。

②Power 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 3.去步骤3。

③Check for electromagnetic interference检查电磁干扰

1. Check for sources of magnetic fields around the vehicle.检查车辆周围是否存在磁场源。 Are the test results normal?检查结果是否正常？ Yes是 Go to step 4.去步骤4。 No否 Move the vehicle away from its current environment.使车辆驶离当前环境。

④Check the vehicle infotainment head unit fault code检查车载智能多媒体主机故障码

1. Use the diagnostic tool to read the fault code of the infotainment head unit and check whether there is a fault in the infotainment head unit.使用诊断仪读取车载智能多媒体主机故障码，检查车载智能多媒体主机是否存在故障。 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 Troubleshoot infotainment head unit faults based on fault codes.根据故障码排除车载智能多媒体主机故障。

⑤Check the gateway controller fault code检查网关控制器故障码

1. Use a diagnostic tool to read the fault code of the gateway controller and check whether there is a fault in the gateway controller.使用诊断仪读取网关控制器故障码，检查网关控制器是否存在故障。 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 Troubleshoot the gateway controller based on the fault code.根据故障码排除网关控制器故障。

⑥Replacing the autonomous driving domain controller更换自动驾驶域控制器

1. Replace with a new autonomous driving domain controller and check whether the fault code and symptoms are eliminated.更换新的自动驾驶域控制器，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 autonomous driving domain controller, you need to use a diagnostic tool to recalibrate the autonomous driving domain controller.更换自动驾驶域控制器后，需用诊断仪对自动驾驶域控制器重新标定。