C156412 - TroubleshootingC156412-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
C156412	EPB switch circuit errorEPB开关回路错误	1.BUTTON wiring harness is short-circuited to ground1.BUTTON线束短路到地
		2.BUTTON harness short circuit to power supply2.BUTTON线束短路到电源
		3.BUTTON wire harness is open circuit3.BUTTON线束断路
		4.Button harness wiring sequence connection error4.Button线束线序连接错误
		5.Button internal failure5.Button内部故障

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。
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 combined switch and clock spring assembly wiring harness is damaged or broken.检查组合开关与时钟弹簧总成线束是否存在损坏、断裂等现象。 3. Check whether the wiring harness connector of the combination switch and clock spring assembly is damaged or has a loose connection.检查组合开关与时钟弹簧总成线束接插件是否存在损坏、虚接等现象。 4. Check whether the wiring sequence connection between the combination switch and the clock spring assembly harness is normal.检查组合开关与时钟弹簧总成线束线序连接是否正常。 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 the combination switch and clock spring assembly wiring harness检查组合开关与时钟弹簧总成线束
	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 integrated brake control unit harness connector FB47 and the combined switch and clock spring assembly harness connector IP31.断开集成式制动控制单元线束接插件FB47和组合开关与时钟弹簧总成线束接插件IP31。 3. Use a digital multimeter to measure the resistance between pins 18/33/9/29 of FB47 and pins 9/10/11/12 of IP31.使用数字万用表测量FB47的18/33/9/29号针脚与IP31的9/10/11/12号针脚之间电阻。 Standard resistance value: <1标准电阻值：＜1 Ω
	d. Use a digital multimeter to measure the resistance between pins 18/33/9/29 of FB47 and ground.d.用数字万用表测量FB47的18/33/9/29号针脚与接地之间的电阻。 Standard resistance value: >1M标准电阻值：＞1M Ω
	e. Connect the negative terminal of the 12V battery, and the power status is "ON".e.连接蓄电池负极，电源状态“ON”。 f. Use a digital multimeter to measure the voltage between pins 18/33/9/29 of FB47 and ground.f.用数字万用表测量FB47的18/33/9/29号针脚与接地之间电压。 Standard voltage value: about 0V标准电压值：约0V 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 faulty wiring harness.维修或更换故障线束。
④Replace the combination switch and clock spring assembly更换组合开关与时钟弹簧总成
1. Replace the combined switch and clock spring assembly with a new one, and check whether the fault code and symptoms are eliminated.更换新的组合开关与时钟弹簧总成，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 5.去步骤5。   Caution:注意： ♦  After replacing the combination switch and clock spring assembly, you need to use a diagnostic instrument to recalibrate the combination switch and clock spring assembly.更换组合开关与时钟弹簧总成后，需用诊断仪对组合开关与时钟弹簧总成重新标定。
⑤Replacing 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。