U012987 - TroubleshootingU012987-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
U012987	There is a communication failure with BCS/IBCS and messages are lost.与BCS/IBCS通讯存在故障，报文丢失	1. Lost communication with BCS/IBCS1.与BCS/IBCS丢失通信

Troubleshooting steps故障诊断步骤

①Power-on inspection (take the left rear blind spot monitoring main sensor as an example for inspection)上电检查(以左后盲区监测主传感器为例进行检查)
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。
②General 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 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。 3. Check whether the ACANFD communication harness connector is damaged or has a loose connection.检查ACANFD通讯线束接插件是否存在损坏、虚接等现象。 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 Repair or replace faulty wiring harness or connector.维修或更换故障线束或接插件。
③Check for electromagnetic interference检查电磁干扰
1. Check for the presence of magnetic fields around the vehicle.检查车辆周围是否存在磁场。 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 the current environment.将车辆驶离当前环境。
④Check ACANFD wiring harness检查ACANFD线束
	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. Disconnect the left rear blind spot monitoring main sensor harness connector RB04 and the integrated brake control unit harness connector FB47.断开左后盲区监测主传感器线束接插件RB04和集成式制动控制单元线束接插件FB47。 3. Use a multimeter to measure the resistance between pin 2/3 of RB04 and pin 13/27 of FB47.使用万用表测量RB04的2/3号针脚与FB47的13/27号针脚之间的电阻。 Standard resistance value: <1标准电阻值：＜1 Ω 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 Repair or replace the faulty wiring harness.维修或更换故障线束。
⑤Check whether the brake control system is working properly检查制动控制系统工作是否正常
1. Check whether the brake control system is working properly.检查制动控制系统工作是否正常。 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 Overhaul the brake control system.检修制动控制系统。
⑥Replace the left rear blind spot monitoring main sensor更换左后盲区监测主传感器
1. Replace with a new left rear blind spot monitoring main sensor and check whether the fault code and symptoms are eliminated.更换新的左后盲区监测主传感器，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 main sensor for monitoring the left rear blind spot, you need to use a diagnostic instrument to recalibrate the main sensor for monitoring the left rear blind spot.更换左后盲区监测主传感器后，需用诊断仪对左后盲区监测主传感器重新标定。