B1C5409 - TroubleshootingB1C5409-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
B1C5409	Evaporator electronic expansion valve EVA under-voltage fault蒸发器电子膨胀阀EVA欠压故障	1.12v power supply system abnormality1.12v供电系统异常

Troubleshooting steps故障诊断步骤

①Power on check上电检查
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 the evaporator electronic expansion valve wiring harness for damage, breakage, etc.检查蒸发器电子膨胀阀线束是否存在损坏、断裂等现象。 3. Check the evaporator electronic expansion valve wiring harness connector for loose connection or damage.检查蒸发器电子膨胀阀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 evaporator electronic expansion valve wiring harness or connector.维修或更换蒸发器电子膨胀阀线束或接插件。
②Check 12V battery voltage检查蓄电池电压
1. Power status is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”,断开蓄电池负极。 2. Use a digital multimeter to measure the voltage between the positive and negative terminals of the 12V battery.用数字万用表测量蓄电池正负极之间的电压。 Standard voltage value: about 12.5V标准电压值：约12.5V 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 Go to step 3.去步骤3。
③Check DCDC output voltage检查DCDC输出电压
1. The vehicle is powered on.车辆上电。 2. Use a digital multimeter to measure the voltage between the positive and negative terminals of the 12V battery.用数字万用表测量蓄电池正负极之间的电压。 Standard voltage value: about 14V标准电压值：约14V Are the test results normal?检查结果是否正常？ Yes是 Charge the 12V battery and replace it if necessary.对蓄电池进行充电，必要时更换蓄电池。 No否 Inspect DCDC and its lines.检修DCDC及其线路。
④Check the evaporator electronic expansion valve supply voltage检查蒸发器电子膨胀阀供电电压
	1. Power on the vehicle and turn on the air conditioner.车辆上电，开启空调。 2. Use a digital multimeter to measure the voltage between pin 1 of the thermal management integrated module harness connector FB44 and ground.用数字万用表测量热管理集成模块线束接插件FB44的1号针脚与接地之间的电压。 Standard voltage value: about 12V标准电压值：约12V 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 Replace the thermal management integrated module.更换热管理集成模块。   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。
⑤Check the voltage drop of the evaporator electronic expansion valve power supply line检查蒸发器电子膨胀阀供电线路电压降
	1. Power on the vehicle and turn on the air conditioner.车辆上电，开启空调。 2. Use a digital multimeter to measure the voltage between pin 1 of the thermal management integrated module harness connector FB44 and pin 1 of the evaporator electronic expansion valve harness connector FB46.用数字万用表测量热管理集成模块线束接插件FB44的1号针脚与蒸发器电子膨胀阀线束接插件FB46的1号针脚之间的电压。 Standard voltage value: <0.4V标准电压值：＜0.4V 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 or replace the evaporator electronic expansion valve power supply harness.维修或更换蒸发器电子膨胀阀供电线束。
⑥Replace the evaporator electronic expansion valve更换蒸发器电子膨胀阀
1. Replace the evaporator electronic expansion valve with a new one, and check whether the fault code and symptoms are eliminated.更换新的蒸发器电子膨胀阀，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。