"Driver Assistance Systems Unavailable" OR Multiple Driver Assist Warnings in Instrument Cluster Message in White and Does Not Self-Clear After a Short Period (A Few Seconds) - Requires Key Cycle/Bus Sleep to Clear - Production Dates before September 5, 2025 or February 27, 2026
Topic number

LI54.71-P-080345

Version

2

Function group

54.71 - Camera and radar-assisted assistance systems

Date

5/19/26

Validity

Model series 174

Reason for change

Removing Cause/Remedy 3.

Complaint
Brief (a few seconds), self-healing "driver assistance systems unavailable" messages are expected and normal due to
system limitations and environmental effects. This can occur during startup of the vehicle but also during driving. No
case is necessary for these. Please refer to the Owner's Manual for driver assistance system limitations and environmental effects.
For "driver assistance systems unavailable" that are persistent or show on every key cycle
AND
Vehicle was produced prior to February 27, 2026.

Cause
Cause 1:
In rare cases, one or more of the fault codes U05B555, U05B655, U05B755 or U05B855 (implausible data was received from the front/rear outer right/left radar sensor. The component part is not configured.) is "Active" in the N62/5
control unit.
This cause mainly occurs in vehicles produced prior to September 5, 2025.
Cause 2:
The initial calibration of the acceleration sensor (IMU) in the N62/5 control unit was not performed/completed.
There is no relevant fault code active in the N62/5 control unit.
This cause mainly occurs in vehicles produced prior to February 27, 2026.

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Remedy
Remedy 1:
Navigate to N62/5 control unit via XENTRY and carry out:
"Adaptations > Teach-in processes > Calibration of the N62/5 control unit (driver assistance system control unit)."
If it is not possible to perform this process or the system is recognizing that all sensors are already calibrated and nothing further needs to be completed, we alternatively recommend carrying out "Calibration drive after exchange of the
component part front bumper or rear bumper" under Teach-in processes.
Once the calibration is started, the calibration screen will appear on the head unit. Xentry will instruct the user to disconnect the device from the vehicle and perform the driving calibration. XENTRY MUST be disconnected and cannot
be left connected.
Remedy 2:
Navigate to N62/5 control unit via XENTRY and carry out:
"Adaptations > Teach-in processes > Calibration of the N62/5 control unit (driver assistance system control unit)."
If there are no identified calibrations, perform calibration drive for the N62/5 control unit. No XENTRY diagnostic device is required for this, as the calibration does not need to be initiated via XENTRY!
Perform a calibration drive of at least 5 minutes and at least 20 turns (left/right evenly distributed) without interrupting
the drive (stop and go is permissible, but no ignition cycling).
The driving speed should be approximately 20 km/h, and the steering wheel angle about 180 degrees (ideal are 90°
turns that must be driven through at more than 10 km/h).
No message is displayed to indicate that the calibration has been successfully completed.
After the calibration drive, the vehicle must be parked and locked for at least seven minutes to allow the vehicle bus to
enter sleep mode.
Once the bus sleep mode has completed, the fault messages should no longer be displayed in the driver display.
Driver support systems may still not be fully available at this time. This is indicated by the ADAS system icons (see
picture ADAS icons).
These are available after a further driving time of approx. 10 minutes.
Connect the vehicle to Mercedes me Connect. MB.Drive, Navigation, and On-Demand features REQUIRE that the vehicle is linked to a profile.
Please also note the additional information regarding the connection between Mandatory Pairing (Head Unit Profile)
and Pre-Delivery Inspection (PDI).

Attachments
File

Description

IMU_Kalibrierung.mp4

Video IMU calibration

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Disclaimer
NOTE: The information contained in this document is intended for use by trained, professional technicians with the
knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz
approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and
provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect
is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a
symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes
resulting in the same or similar symptoms or conditions described in this document, and trained professional service
technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained
in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.

Symptoms
Communication/information > Assistance and warning systems > Distronic > Function > Warning message in instrument cluster
Communication/information > Assistance and warning systems > Brake Assist > Warning message in instrument
cluster
Communication/information > Assistance and warning systems > Blind spot assist > Warning message in instrument
cluster

Control unit/fault code
Control unit

Fault text

N62/5 - Driver assistance system (SG-FAS)
(IDC_GEN6_P)

U05B855 - Implausible data were received from the outer
right rear radar sensor. The component is not configured.
U05B755 - Implausible data were received from the outer
left rear radar sensor. The component is not configured.
U05B655 - Implausible data were received from the outer
right front radar sensor. The component is not configured.
U05B555 - Implausible data were received from the outer
left front radar sensor. The component is not configured.

Operation numbers/damage codes
Op. no.

Operation text

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Time

Damage
code

ZM

540K6F1

SAHARRY

Note

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