2017 Mercedes Benz S 63 AMG Technical Service Bulletin # LI32-50_P-048280 Date: 091110

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Suspension - ABC Suspension Humming/Buzzing Noise
HUMMING/HOWLING NOISE FROM ABC SUSPENSION UP TO APPROX. 2000 RPM
Topic number LI32.50-P-048280
Version 1
Design group 32.50 Active body control (ABC)
Date 11-10-2009
Validity MODEL 215, 216.37#, 220, 221, 230 with code 487
(ABC); all vehicles with Active Body Control (code 487)
Reason for change Validity extended to current model series / Supersedes DTB P-B-32.50/24
Reason for block
Complaint:
Humming / howling noises can be heard from underfloor area.
Noise can be heard from idle up to approx. 2000 rpm. Above this, it is drowned out by the engine noise.
Note:
The noise is particularly noticeable at approx. 1400 rpm.
Cause:
As mileage increases (>100,000 km / 62,000 miles), the gas pressure in the pulsation damper ("pressure reservoir" / "damper") of the ABC system
can decline, meaning that the full damping effect may no longer be available.
Note:
Noises may also be caused by touching/stressed ABC lines. Please check this before replacing any parts, and correct if necessary.
Aids:
Use clamp kit for noise diagnosis (STEELMAN ChassisEAR) as per WIS document (AR32.00-P-2000A).
Remedy:
If ABC lines are not touching / stressed,
replace pulsation damper at pressure supply valve block (ABC I) or at tandem pump (ABC-PLUS).
Note:
Pulsation damper can be replaced separately, sealing ring is included.
Note:
Replacement of the entire pressure supply valve unit or ABC tandem pump is not required.
Note:
With the introduction of ABC-PLUS (as of model year 2006), the pulsation damper is located on the tandem pump.
Attachments
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Symptoms
Parts
Work Units
WIS-References
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Validity
Attachment - Pulsation damper: No. 410
Attachment - Pulsation damper: No. 290 Valid up to model year 2006
Attachment - Pulsation damper: No. 15