LI32.50-P-072071

Noise Complaints Relating To The eSuspension
Topic number
LI32.50-P-072071
Version
2
Function group
32.50 - Active Body Control (ABC)
Date
7/7/21
Validity
Model series 167 with SA code 489/AIRMATIC and with
SA code 490/eSuspension. Except AMG model designations.
Reason for change
Incorporation of GLE after note regarding Russian market
Complaint
1. Noises in recovery mode with the vehicle stationary
2. Noises when driving in a straight line on rough terrain
3. Noises when cornering and performing alternate steering movements
4. Non-assignable noises
Attachments
File
Description
BouncingNoise.MOV
1. and 2. Normal operating noises of the high-pressure
pump in recovery mode and when driving in a straight line
on rough terrain.
VID_20200907_165939_cut.mp4
3.Reversing noise of the high-pressure pump when steering quickly in the opposite direction
Cause
Complaint 1. Noises in recovery mode with the vehicle stationary
Complaint 2. Noises when driving in a straight line on rough terrain
These are normal operating noises of the hydraulic high-pressure pumps.
Explanation:
This is the "preview noise" which is heard when recovery mode is in operation, but which can also occur when driving
over very uneven ground in the Comfort and Curve drive programs.
This is a normal operating noise which is caused by the hydraulic high-pressure pumps (MPE).
To compensate for the unevenness of the ground, large oil flows need to be generated and to do so, the MPEs turn at
very high rotational speeds.
Note:
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In the "ECO" drive program, the "Preview" function is deactivated so these noises should not occur when driving over
uneven terrain; however the vehicle body will move noticeably.
Complaint 3. Noises when cornering and performing alternate steering movements - reversing noise.
Repeated rapid steering out of a curve generates a "grunting" noise.
Explanation:
This noise is caused by the MPEs when the pump's direction of rotation is reversed.
Note: The reversing noise can occur in all drive programs, but is most clearly reproducible in the Curve drive program
and in Curve level 3.
Carry out an evaluation firstly in Curve levels 1 to 3 (at the highest Curve level 3, the noise will also be at its loudest),
and then in the Comfort drive program.
Complaint 4. Non-assignable noises
For procedure, see Remedy.
Remedy
Check whether the same noises also occur in ECO mode - in this mode the Preview/ROAD SURFACE SCAN function
is deactivated and the high-pressure pumps run at reduced speed.
Consequently, it is possible to differentiate between normal operating noises and unusual noises.
Regarding 1, 2: Explain the high-pressure system, replacing the suspension struts or pumps is not useful, as these
noises are caused by the high-pressure pump unit and should be regarded as normal operating noises.
Regarding 3: This is currently a normal operating noise and represents the series production configuration; consequently replacing the components is not useful.
Regarding 4: There will certainly be other unknown noises that we are not yet familiar with; therefore please report
these.
For all complaints, create a PTSS case and include:
•
Informative video recordings of the noises.
•
The driving situation in the drive program in which the noises occur should be shown.
•
For comparison, also attach a recording of this same driving situation in ECO mode.
Additional attachments required:
•
•
Logs for control units N51/8, M67, M67/1, M67/2, M67/3
Actual values for the pressures of the four hydraulic high-pressure pumps at standstill
Symptoms
Chassis/suspension > Suspension/Dampening > Suspension system noises > whistles/hisses
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Parts
Part number
ES1 ES2 Designation
Quantity Note
EPC
A1673209601
Hydraulic pump, right front
1
Replacement of part is not useful,
create a TIPS case
X
A1673209501
Hydraulic pump, left front
1
Replacement of part is not useful,
create a TIPS case
X
A1673209701
Hydraulic pump, left rear
1
Replacement of part is not useful,
create a TIPS case
X
A1673209801
Hydraulic pump, right rear
1
Replacement of part is not useful,
create a TIPS case
X
A1673202904
Suspension strut, front left and 2
right
Replacement of part is not useful,
create a TIPS case
X
A1673206204
Right rear shock absorber
1
Replacement of part is not useful,
create a TIPS case
X
A1673207403
Right rear shock absorber
1
Replacement of part is not useful,
create a TIPS case
X
A1673206104
Left rear shock absorber
1
Replacement of part is not useful,
create a TIPS case
X
A1673207303
Left rear shock absorber
1
Replacement of part is not useful,
create a TIPS case
X
Control unit/fault code
Control unit
Fault text
M67 - Electrohydraulic controller unit LEFT FRONT
(EHSE)
M67/1 - Electrohydraulic controller unit RIGHT FRONT
(EHSE)
M67/2 - Electrohydraulic controller unit LEFT REAR
(EHSE)
M67/3 - Electrohydraulic controller unit RIGHT REAR
(EHSE)
N51/8 - Active suspension and damping system (Active
suspension)
Operation numbers/damage codes
Op. no.
Operation text
07.07.2021 15:46:14
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Time
JKANTAR
Damage
code
Note
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