Swing the steering wheel is something that everyone has to do every day, but one day suddenly the instrument steering wheel fault light is on, and the instrument and display screen also prompt "active steering system failure!"! When turning, please pay attention. "Do you panic? Don't panic. I hope the following dry goods can bring you peace of mind.

先了解下宝马的主动转向系统

First understand BMW's active steering system

1、原理

1, principle

宝马主动转向系统主要由转向器、转向助力泵(集成液压泵)、电动调节阀、液压油储油罐、液压油冷却器和一些执行元件组成。它与传统的转向系统外观上看类似，只是在传统转向系统的齿轮与齿条间增加了双行星齿轮机构，用于给前轮提供叠加转向角。

BMW active steering system mainly consists of steering gear, power steering pump (integrated hydraulic pump), electric control valve, hydraulic oil storage tank, hydraulic oil cooler and some actuator components. It is similar to the traditional steering system in appearance, except that a double planetary gear mechanism is added between the gear and rack of the traditional steering system to provide the superimposed steering angle for the front wheels.

也就是说，主动转向系统用的是重叠式转向器，它主要由行星齿轮机构、涡轮、蜗杆传动机构、伺服电机、伺服电机位置传感器、电磁锁等组成。主动转向系统根据车速、转向角等信号控制伺服电机，该伺服电机与蜗杆传动机构固定连接在一起并以无间隙的方式嵌入涡轮内，从而得以驱动行星齿轮组件，进而实现调节转向角、改变转向传动比的目的。电动机转动的方向、转速和持续运行时间由伺服电机位置传感器进行监控，以便计算冗余转向角。

In other words, the active steering system uses overlapping steering gear, which is mainly composed of planetary gear mechanism, turbine, worm drive mechanism, servo motor, servo motor position sensor, electromagnetic lock, etc. The active steering system controls the servo motor according to the speed, steering angle and other signals. The servo motor is fixedly connected with the worm drive mechanism and embedded in the turbine in a gapless way, so that the planetary gear components can be driven, and the purpose of adjusting the steering angle and changing the steering transmission ratio can be realized. The direction, speed and duration of motor rotation are monitored by servo motor position sensor to calculate redundant steering angle.

2、优点

2, advantages

主动转向系统，转向机是可变传动比的，也就是说转向盘的转角与车轮转角的对应关系是可变的。那么，主动转向系统就可以根据具体的行驶情况，在驾驶员转动方向盘的时候，主动增加或减小前轮的转向角。通俗点说，就是在车辆静止或低速的时候，驾驶员打方向盘只需要一个小幅度，就可以实现前轮的较大的转向角；而在高速的时候，驾驶员打方向盘需要一个很大的幅度，才能实现前轮一个较小的转向角，从而消除了高速转向的漂移现象。这样，不管高速低速，驾驶员都能获得一个良好的转向手感。

In active steering system, the steering gear has variable transmission ratio, that is to say, the corresponding relationship between steering wheel angle and wheel angle is variable. Then, the active steering system can actively increase or decrease the steering angle of the front wheels when the driver turns the steering wheel according to the specific driving conditions. Generally speaking, when the vehicle is stationary or at low speed, the driver only needs a small range to turn the steering wheel to achieve a larger steering angle of the front wheel; while at high speed, the driver needs a large range to turn the steering wheel to achieve a smaller steering angle of the front wheel, thus eliminating the high-speed steering drift. In this way, regardless of high speed and low speed, the driver can get a good steering feel.

再来说说主动转向系统失灵的原因

Let's talk about the cause of active steering system failure

1、常见的几个原因有：

1. There are several common reasons:

a、转向角传感器故障；

a. Steering angle sensor failure;

b、伺服电机位置传感器故障；

b. Servo motor position sensor fault;

如果拿去诊断，发现有转向角传感器或伺服电机位置传感器相关的故障码，那故障点估计没跑，检查相关传感器及其相关线束一般就能解决。这里要注意的是伺服电机位置传感器在4S肯定是不能单独换的，所以，如果出保，可以尝试维修芯片。

If there is a fault code related to the steering angle sensor or servo motor position sensor when it is taken for diagnosis, the fault point is estimated not to run. Generally, it can be solved by checking the relevant sensor and its related harness. It should be noted that the position sensor of servo motor cannot be replaced separately in 4S shop, so if it is out of warranty, you can try to repair the chip.

c、转向柱模块故障

c. Steering column module failure

这里说一个比较无语的原因，就是转向柱开关(SZL)内部太脏了，导致转角信号太弱，电脑检测不到或者检测到的信号不可信，于是就报故障了，我们清理干净就好，特别是转角传感器清理干净。这个问题说实话拆卸清理费力不赚钱，是让你换还是给你清理就看你运气了，不过一般是运气不好哈。

The reason why there is no speech here is that the steering column switch center (SZL) is too dirty, which causes the corner signal to be too weak, the computer can't detect or the detected signal is not credible, so the fault is reported, we can clean it up, especially the corner sensor. To be honest, dismantling and cleaning are laborious and do not make money. It depends on your luck whether you want to change or clean it up, but it's usually bad luck.

这里简单说一下故障原理：转角信号是由发光二极管经过透镜和光栅到达接收二极管产生，如果透镜变脏，那么光线传播过程中就会损失，信号自然就变弱了。

Here's a brief introduction to the fault principle: the corner signal is generated by the light-emitting diode passing through the lens and grating to the receiving diode. If the lens becomes dirty, the light will be lost in the process of propagation, and the signal will naturally become weak.

d、轮速传感器故障

d. Wheel speed sensor failure

如果仪表还有DSC的故障灯，那轮速传感器及其线路也可以关照下。

If the instrument still has the fault lamp of DSC, the wheel speed sensor and its circuit can also be focused on.

2、通信问题导致主动转向系统失灵

2. Communication problems lead to active steering system failure

主动转向系统一般是通过F-CAN总线接受各种传感器、控制模块的信号和数据，然后通过PT-CAN与发动机电脑、安全和网关模块进行数据传输，所以如果检测出通信问题，那可以先排查总线。

Active steering system generally receives signals and data from various sensors and control modules through f-can bus, and then transmits data with engine computer, safety and gateway module through pt-can. If communication problems are detected, the bus can be checked first.

3、方向机线束老化漏电

3. Aging and leakage of steering harness

如果去诊断没明显的故障码，又匹配不了方向机，在怀疑方向机准备更换的情况下，不妨检查下方向机线束，可能就省钱了呢。

If there is no obvious fault code to diagnose, and it can't match the steering machine, if you suspect that the steering machine is ready to be replaced, you may as well check the wiring harness of the steering machine, which may save money.

4、电瓶存电量不足

4. Storage capacity of battery is insufficient

如果你经常冷车启动时候报主动转向失灵，方向盘很重，可是行驶一段时间后又一切正常了，那么可以怀疑是不是电瓶不行，要更换了。

If you often report that the active steering fails when you start a cold car, and the steering wheel is heavy, but after a period of driving, everything is normal, then it can be doubted that the battery is not working. It needs to be replaced.