e38 的電子懸吊 如何檢測這些是否正常...在

[lyh1216]

因為e38 的電子懸吊軟硬 受以下感應器動態調整
但感覺它的作動異常
一般模式 : 有時會一直在中等硬度( "medium) . 不會變軟("soft) " 即使是路況變好也不會跳到變軟(soft)
將避震器relay 拔掉 重新發動 有時又正常 ..但行駛一段後又會一直在中等硬度( "medium) . 不會變軟("soft)
以GT1去驅動測試 它是可以 3段都可以調整
到底是 哪裡有異常 ?
下面 是E38 EDC III Plus基本資訊:
這些傳感器的數據依賴於有關的駕駛情況，EDC的阻尼器控制單元開關
決定減震器的“軟”，“中等”或“硬”

1.轉向角傳感器 Steering angle sensor
(是否有偏差 如何重整 設定)
2.前加速度傳感器 Front acceleration sensor
(到底在什麼位置 如何檢測)
3.後加速度傳感器 Rear acceleration sensor

Electronic damper control III Plus
The electronic damper control III Plus (EDC III +) is an electronic damping force control system.The aim of the
system is to adapt the necessary damping force of the vibration dampers to current driving and road
conditions such that maximum driving safety is achieved in conjunction with the highest possible degree of
comfort.
For this purpose, the system features following sensors to record the driving situation: Steering angle sensor,
speed sensor, front body acceleration sensor, rear body acceleration sensor.
Dependent on these sensor data relating to the driving situation, the EDC control unit switches the damper
valves integrated in the shock absorbers in the stages "soft", "medium" or "hard".
With the aid of the EDC program button, the driver has the option of selecting two different programs:The
"Sports program" is selected in button position "S" and the "Comfort program" in button position "K".In the
sports program, the dampers are switched more rigidly oriented, i.e. the damper setting "soft" is avoided. In
setting "K", all three switching stages are operated, i.e. there is a sports and a comfort characteristic curve.
Since the EDC programs ("Sports" and "Comfort") are selected by means of a button (no rocker switch), only
the LED integrated in the button indicates which program is currently selected. When the LED at the "S"
symbol lights, the EDC operates in the"Sports program", if the LED is off the system is operating in the
"Comfort program".This, of course, only applies if the EDC system is intact.
Important!
If the EDC system is not operable (e.g. one sensor defective) or faulty to such an extent that reliable road
adhesion can no longer be guarantied under all conditions, the safety concept (integrated in the software of
the EDC control unit) switches off the entire EDC system.In this case, the LED in the selector switch goes out
even if the "Sports program" is active. To ensure continued save vehicle operation in the event of such a
system failure, the power supply to the damper valves is cut, i.e. they are operated in the fixed stage
"hard".Although vehicle damping is then rigid, it can be further operated without any loss in road adhesion and
the next service workshop can be visited safely.
General information
The EDC III Plus system has diagnostic capabilities.Disturbances on the supply and signal lines of the
damper valves, defects and illogical behaviour of the system sensors and their corresponding lines are stored
in the defect code memory of the control unit.
Note
Faults in the EDC system found by the defect code memory can be examined and rectified by way of the
program point "Test modules".
EDC program button
In line with the operating philosophy of the E38, the EDC programs are selected by means of a button (in
contrast to the rocker switch in earlier EDC systems).
The program button is marked with "K" for "Comfort program" and "S" for "Sports program".
When the sports program is selected, the LED lights at the "S" symbol.The LED remains off when the comfort
program is selected.
The button lighting is dimmed when the headlights are switched on.
Important!
If operation of the EDC III Plus system is persistently disturbed, the system is switched off, the LED in the
program button remains off.
Steering angle sensor
The task of the steering angle sensor is to record the steering wheel angle while driving.
The EDC control unit processes both the real steering angle as well as the steering angle speeds, i.e.
changes in angle. In this way, the variables of the steering angle as well as the steering angle speed have an
influence on the switching logic of the EDC system.
The steering angle sensor is mounted on the steering column spindle.The sensor consists of 2 wipers offset
by 90 degrees. The measuring range of the steering angle sensor extends from 180 degrees left to 180
degrees right and the straight-ahead position, i.e. the centre position of the steering wheel marks the 0 degree
Electronic damper control III Plus Page 1 of 3
http://www.bmw-planet.com/diagrams/release/en/zinfo/B3715_01.htm 18/08/2009
setting.
Important!
If the steering angle sensor is changed or if it is necessary to carry out work on the front axle system, front
wheels/steering system, the so-called steering angle offset must be carried out on completion of this work.The
diagnosis program is used for this purpose.
The steering angle offset is selected under the point SERVICE FUNCTIONS. After setting the front wheels in
the straight ahead-position, the control unit carried out the offset procedure automatically after pressing the
confirmation button. The 0 degrees setting of the steering angle sensor now agrees with the physical straightahead
position of the front wheels.
Slight deviations which may occur because the straight-ahead position of the steering wheels can only be set
by eye, are compensated by the EDC control unit itself when driving.
The EDC control unit powers the steering angle sensor with a 5 Volt supply.Data transfer to the control unit
takes place via 2 signal lines.
Front acceleration sensor
The front acceleration sensor records the acceleration of the car body at the front in vertical direction.
The body acceleration is caused by the reaction of the car to the road surface. In addition to the absolute
acceleration, the acceleration frequency is also recorded, i.e. the changes in acceleration (spring
deflection/rebound), in other terms the vibration frequency of the vehicle body.
The acceleration sensor receives a 12 Volt supply from the control unit.
A voltage value between 0 and 5 Volt is output to the control unit at the signal output of the sensor. A value of
2.5 Volt represents the rest position (acceleration = 0), the values 0 Volt and 5 Volt are the maximum
acceleration values.
Important!
In order to check the function of the sensor, "front acceleration sensor" can be selected in the diagnosis
program under the point "Function test".
Checking outside the vehicle:
Remove sensor, connect to 12 Volt supply and check the function by measuring the voltage at the signal
output while at the same time moving the sensor. If the sensor is operating correctly, the measured voltage
value is varied between approx. 0 and 5 Volt (depending on degree of movement, i.e. acceleration
magnitude).
Installation location of sensor:Right-hand spring strut dome on side panel behind splash guard.
Rear acceleration sensor
The rear acceleration sensor records the acceleration of the vehicle body at the rear in vertical direction.
The body acceleration is caused by the reaction of the vehicle to the road surface.In addition to the absolute
acceleration, the acceleration frequency is also recorded, i.e. the changes in acceleration (spring
deflection/rebound), in other terms the vibration frequency of the vehicle body.
The acceleration sensor receives a 12 Volt supply from the control unit.
A voltage value between 0 and 5 Volt is output to the control unit at the signal output of the sensor. A value of
2.5 Volt represents the rest position (acceleration = 0), the value 0 Volt and 5 Volt are the maximum
acceleration values.
Important!
In order to check the function of the sensor, "front acceleration sensor" can be selected in the diagnosis
program under the point "Function test".
Checking outside the vehicle:
Remove sensor, connect to 12 Volt supply and negative and check function by measuring voltage at signal
output while at the same time moving the sensor.If the sensor is operating correctly, the measured voltage
value will vary between approx. 0 and 5 Volt (depending on movement, i.e. acceleration magnitude).
Installation location of sensor:Rear RH spring dome, accessible from luggage compartment after removing the
trim.
EDC valves for chassis dampers
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http://www.bmw-planet.com/diagrams/release/en/zinfo/B3715_01.htm 18/08/2009
Newly developed vibration dampers with integrated valves operate in the EDC III Plus system. Contact of the
connection is made by the piston rod.
The two valves are switched in combination such that three damping force stages are made possible:Damper
stage "hard", damper stage "medium" and damper stage "soft".
In addition to the more compact design compared to the old EDC system, it has also been possible to reduce
the weight of the new dampers.
Speed signal
The EDC control unit receives its speed signals from the front left wheel speed sensor of the ABS system.
From this speed sensor, the signal is transferred to the ABS control unit which in turn sends the signal to the
EDC control unit. The speed signal received by the EDC control unit is a square-wave signal (0 to 12 VOLT).
The corresponding cornering speed/lateral acceleration is calculated on the basis of the measuring variables
vehicle speed and steering wheel angle.
Calculating the change in vehicle speed renders a longitudinal acceleration sensor unnecessary.
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http://www.bmw-planet.com/diagrams/release/en/zinfo/B3715_01.htm 18/08/2009

[aries0512]

GT1 EDC選項下有方向盤角度感知器的歸零功能。
右前感知器應是在右前輪內龜內，要拆塑膠防土內襯。可能也只能以GT1測試感知器。

[lyh1216]

tks