C003801 - TroubleshootingC003801-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
C003801	Left rear wheel speed sensor failure - power supply voltage is too low左后轮轮速传感器故障—电源电压过低	1. Abnormal power supply to left rear wheel speed1.左后轮轮速供电异常

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 the power supply line of the left rear in-line wheel speed sensor检查左后直插式轮速传感器供电线路
	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 integrated brake control unit harness connector FB47 and the left rear in-line wheel speed sensor harness connector CA03.断开集成式制动控制单元线束接插件FB47和左后直插式轮速传感器线束接插件CA03。 3. Use a digital multimeter to measure the resistance between pin 38/23 of FB47 and pin 1/2 of CA03.使用数字万用表测量FB47的38/23号针脚与CA03的1/2号针脚之间的电阻。 Standard resistance value: <1标准电阻值：＜1 Ω
	d. Use a digital multimeter to measure the resistance between pin 38 of FB47 and ground.d.用数字万用表测量FB47的38号针脚与接地之间的电阻。 Standard resistance value: >1M标准电阻值：＞1M Ω 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 the faulty wiring harness.维修或更换故障线束。
③Replace the left rear in-line wheel speed sensor更换左后直插式轮速传感器
1. Replace with a new left rear in-line wheel speed sensor and check whether the fault code and symptoms are eliminated.更换新的左后直插式轮速传感器，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 Go to step 4.去步骤4。
④Replacing the integrated brake control unit更换集成式制动控制单元
1. Replace with a new integrated brake control unit and check whether the fault code and symptoms are eliminated.更换新的集成式制动控制单元，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 integrated brake control unit, you need to use a diagnostic tool to recalibrate the integrated brake control unit.更换集成式制动控制单元后，需用诊断仪对集成式制动控制单元重新标定。 ♦  After replacing the integrated brake control unit, the brake line bleeding operation is required.更换集成式制动控制单元后，需进行制动管路排气操作。