Blind Spot Assist inoperative
Topic number

LI54.71-P-056477

Version

11

Function group

54.71 Camera and radar-assisted assistance systems

Date

08-07-2019

Validity

All MB cars with code 234 (Blind Spot Assist) or code 237
(Active Blind Spot Assist)

Reason for change

Damage code adapted

Reason for block

Complaint:

Blind Spot Assist inoperative.

Cause:

Moisture.
Important: For BR 117, 156, 176, 246 with code 234 (Blind Spot Assist), also observe LI54.71-P-066010.
Example information on diagnosis on selected model series:
BR166/204 with code 234 (Blind Spot Assist):
•
•
•

Malfunctions on the engine compartment CAN (CAN C) are possible
In control units on the CAN C, CAN communication errors may be logged with the rear short-range radar sensors (IRS-HLA B29/4 and IRS-HRA B29/5 control units).
Diagnostic communications with control units on the CAN C may not be possible.

BR212/218 up to code 800 (Model year 2010) with code 234 (Blind Spot Assist):
•
•
•

Malfunctions on the sensor CAN (CAN S) are possible
In the radar sensors control unit (N62/1), CAN communication errors may be logged with the rear short-range radar sensors (B29/6 and B29/7).
Communications with control units on the CAN S may not be possible.

BR212/218 as of code 801 (Model year 2011) with code 234 (Blind Spot Assist):
•
•
•

Malfunctions on the front end CAN (CAN G) are possible
Control units on the CAN G may exhibit CAN communication errors with the rear short-range radar sensors
(IRS-HLA B29/4 and IRS-HRA B29/5 control units).
Diagnostic communications with control units on the CAN G may not be possible.

BR166/204/212/218 with code 237 (Active Blind Spot Assist):
•
•

Malfunctions on the sensor CAN (CAN S) are possible
In the video and radar sensor system control unit (N62/2), CAN communication errors may be logged with the
rear short-range radar sensors (B29/6 and B29/7).

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•

Communications with control units on the CAN S may not be possible.

Remedy:
1.
2.
3.
4.

Remove rear bumper.
Remove rear short-range radar sensors, check connector/contact for corrosion and repair if necessary.
Installation of short-range radar sensor (see EPC).
Install rear bumper.

Symptoms
Overall vehicle / Networking / CAN/FlexRay communication / Malfunction
Overall vehicle / Networking / Diagnosis/software / Not diagnosable
Communication/information / Assistance and warning systems / Blind spot assist / No warning
Communication/information / Assistance and warning systems / Blind spot assist / Display without obvious cause
Communication/information / Assistance and warning systems / Blind spot assist / Warning message in instrument
cluster
Communication/information / Assistance and warning systems / Blind spot assist / Malfunction

Control unit/fault code
Control unit

Fault code

Fault text

B29/5 - Outer right rear intelligent radar sensor system
(IRS-HRA) (IBSM212_R1)
(B (242, 246),M/GLE (166),E
(212),C (204),GLK (204),CLS
(218))

-

-

B29/4 - Outer left rear intelligent radar sensor system
(IRS-HLA) (IBSM212_R4) (E
(212))

-

-

B29/5 - Outer right rear intelligent radar sensor system
(IRS-HRA) (IBSM3G_R1)

-

-

B29/4 - Outer left rear intelligent radar sensor system
(IRS-HLA) (IBSM3G_R4)

-

-

N62/1 (Radar sensors control unit) (RDU_212) (GL/GLS
(166),M/GLE (166),SLK/SLC
172,E (212),C (204),GLK (204)
,CLS (218))

-

N62/1 (Radar sensors control unit) (RDU_212FR) (GL/GLS
(166),M/GLE (166),SLK/SLC
172,E (212),C (204),GLK (204)
,CLS (218))

-

N62/1 (Radar sensors control
unit) (VRDU) (M/GLE (166),E
(212),CLS (218))

-

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-

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Operation numbers/damage codes
Op. no.

Operation text

Time

Damage
code

54-1975

REPLACE REAR SENSOR UNIT OF
BLIND SPOT ASSIST, QUANTITY:.....
(BUMPER REMOVED)

54H13 G1

88-8802

REMOVE/INSTALL REAR BUMPER
COMPLETE

54H13 G1

Note

WIS-References
Document number

Title

Note

Allocation

AR54.71-P-0100EW

Remove/install sensors for
Blind Spot Assist

Model series 212

Remedy

AR88.20-P-2200EW

Remove/install rear bumper Model series 212

Remedy

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