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.

先了解下寶馬的主動轉向系統

First understand BMW's active steering system

1、原理

1, principle

寶馬主動轉向系統主要由轉向器、轉向助力泵(集成液壓泵)、電動調節閥、液壓油儲油罐、液壓油冷卻器和一些執行元件組成。它與傳統的轉向系統外觀上看類似，只是在傳統轉向系統的齒輪與齒條間增加了雙行星齒輪機構，用于給前輪提供疊加轉向角。

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.

也就是說，主動轉向系統用的是重疊式轉向器，它主要由行星齒輪機構、渦輪、蝸桿傳動機構、伺服電機、伺服電機位置傳感器、電磁鎖等組成。主動轉向系統根據車速、轉向角等信號控制伺服電機，該伺服電機與蝸桿傳動機構固定連接在一起并以無間隙的方式嵌入渦輪內，從而得以驅動行星齒輪組件，進而實現調節轉向角、改變轉向傳動比的目的。電動機轉動的方向、轉速和持續運行時間由伺服電機位置傳感器進行監控，以便計算冗余轉向角。

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、優點

2, advantages

主動轉向系統，轉向機是可變傳動比的，也就是說轉向盤的轉角與車輪轉角的對應關系是可變的。那么，主動轉向系統就可以根據具體的行駛情況，在駕駛員轉動方向盤的時候，主動增加或減小前輪的轉向角。通俗點說，就是在車輛靜止或低速的時候，駕駛員打方向盤只需要一個小幅度，就可以實現前輪的較大的轉向角；而在高速的時候，駕駛員打方向盤需要一個很大的幅度，才能實現前輪一個較小的轉向角，從而消除了高速轉向的漂移現象。這樣，不管高速低速，駕駛員都能獲得一個良好的轉向手感。

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.

再來說說主動轉向系統失靈的原因

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

1、常見的幾個原因有：

1. There are several common reasons:

a、轉向角傳感器故障；

a. Steering angle sensor failure;

b、伺服電機位置傳感器故障；

b. Servo motor position sensor fault;

如果拿去診斷，發現有轉向角傳感器或伺服電機位置傳感器相關的故障碼，那故障點估計沒跑，檢查相關傳感器及其相關線束一般就能解決。這里要注意的是伺服電機位置傳感器在4S肯定是不能單獨換的，所以，如果出保，可以嘗試維修芯片。

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、轉向柱模塊故障

c. Steering column module failure

這里說一個比較無語的原因，就是轉向柱開關(SZL)內部太臟了，導致轉角信號太弱，電腦檢測不到或者檢測到的信號不可信，于是就報故障了，我們清理干凈就好，特別是轉角傳感器清理干凈。這個問題說實話拆卸清理費力不賺錢，是讓你換還是給你清理就看你運氣了，不過一般是運氣不好哈。

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.

這里簡單說一下故障原理：轉角信號是由發光二極管經過透鏡和光柵到達接收二極管產生，如果透鏡變臟，那么光線傳播過程中就會損失，信號自然就變弱了。

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、輪速傳感器故障

d. Wheel speed sensor failure

如果儀表還有DSC的故障燈，那輪速傳感器及其線路也可以關照下。

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

2、通信問題導致主動轉向系統失靈

2. Communication problems lead to active steering system failure

主動轉向系統一般是通過F-CAN總線接受各種傳感器、控制模塊的信號和數據，然后通過PT-CAN與發動機電腦、安全和網關模塊進行數據傳輸，所以如果檢測出通信問題，那可以先排查總線。

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、方向機線束老化漏電

3. Aging and leakage of steering harness

如果去診斷沒明顯的故障碼，又匹配不了方向機，在懷疑方向機準備更換的情況下，不妨檢查下方向機線束，可能就省錢了呢。

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、電瓶存電量不足

4. Storage capacity of battery is insufficient

如果你經常冷車啟動時候報主動轉向失靈，方向盤很重，可是行駛一段時間后又一切正常了，那么可以懷疑是不是電瓶不行，要更換了。

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.