LI82.70-P-064726 Service Bulletin/Repair Instructions

Mobile phone and VCS: Poor call quality and/

or voice control misunderstands commands

Topic number
LI82.70-P-064726
Version
6
Function group
82.70 Telephone, Voice-control-system(VCS)
Date
11-19-2020
Validity
Model series 213, 238, 177, 167, 118, 247

Model series 253 Facelift
Reason for change
Remedy updated
Reason for block
Complaint:
The following complaints may be noted by the customer:

- During a phone call, the called party may have difficulty understanding the drivr/passenger, or interference/background noises are audible to the called party during a call

- Voice control does not understand or misunderstands spoken commands

- Voice control does not activate with the "Hey Mercedes" keyword (NTG6 equipped vehicles only)
Cause:
- Installation of microphones (B25/20, B25/21) in the headliner

- Debris inside the microphone housing

- Microphone hardware

- Wiring between microphone and head unit (A26/17) --> See PE82.85-P-2110-97DBA (213 model series) or

PE82.85-P-2110-97IBA (177 model series) for reference
Remedy:
Before proceeding process any relevant fault codes and perform the recommended guided tests per XENTRY diagnosis.

Check installation of both microphones (B25/20 and B25/21):

- Check for and remove any foreign debris located between the microphone and the microphone cover

- Reinstall microphone into headliner ensuring that microphone cover is fully seated onto the microphone housing.

You should feel it "click" once it is seated properly

- Re-test functionality

If the complaint is still present after the above measures:

- Replace both microphones (B25/20 and B25/21) and both microphone covers

- Re-test functionality

11-19-2020 10:57 PM

© Copyright Mercedes-Benz AG
CTENORE
Page 1/3
If the complaint still persists after the microphone and microphone cover replacements, check the wiring between the

microphones, the intermediate microphone electrical connector in the headliner, and the head unit (A26/17)

- Check connectors to ensure they are fully seated and inspect connectors, wiring, and pins for damage

- Check continuity from the microphone to microphone electrical connector and from the electrical connector to the

head unit

- Ensure that pins are wired correctly, i.e. ensure the signal and ground wires are not switched in the connector
Symptoms

Communication/information / Communication / Voice control system VCS / Input is not understood

Communication/information / Communication / Mobile phone / Telephone / Poor understanding

Communication/information / Communication / Mobile phone / Telephone / Driver cannot be heard

Communication/information / Communication / Mobile phone / Telephone / Driver can be poorly/hardly heard
Control unit/fault code

Control unit
Fault code
Fault text
A26/17 - Audio or COMAND

B143A11

(Head unit) (HU55) (GLC (253)

,E (213),E (238))
Microphone 1 has a malfunction. There is a short circuit to

ground.
A26/17 - MBUX multimedia sy- B143D13

stem (Head unit) (HU6)
Microphone 2 has a malfunction. There is an open circuit.
A26/17 - MBUX multimedia sy- B143A13

stem (Head unit) (HU6)
Microphone 1 has a malfunction. There is an open circuit.
A26/17 - MBUX multimedia sy- B143A11

stem (Head unit) (HU6)
Microphone 1 has a malfunction. There is a short circuit to

ground.
A26/17 - Audio or COMAND

B143A12

(Head unit) (HU55) (GLC (253)

,E (213),E (238))
Microphone 1 has a malfunction. There is a short circuit to positive.
A26/17 - Audio or COMAND

B143A13

(Head unit) (HU55) (GLC (253)

,E (213),E (238))
Microphone 1 has a malfunction. There is an open circuit.
A26/17 - Audio or COMAND

B143D11

(Head unit) (HU55) (GLC (253)

,E (213),E (238))
Microphone 2 has a malfunction. There is a short circuit to

ground.
A26/17 - Audio or COMAND

B143D12

(Head unit) (HU55) (GLC (253)

,E (213),E (238))
Microphone 2 has a malfunction. There is a short circuit to positive.
A26/17 - Audio or COMAND

B143D13

(Head unit) (HU55) (GLC (253)

,E (213),E (238))
Microphone 2 has a malfunction. There is an open circuit.
A26/17 - MBUX multimedia sy- B143D11

stem (Head unit) (HU6)
Microphone 2 has a malfunction. There is a short circuit to

ground.
A26/17 - MBUX multimedia sy- B143A12

stem (Head unit) (HU6)
Microphone 1 has a malfunction. There is a short circuit to positive.
A26/17 - MBUX multimedia sy- B143D12

stem (Head unit) (HU6)
Microphone 2 has a malfunction. There is a short circuit to positive.
11-19-2020 10:57 PM

© Copyright Mercedes-Benz AG
CTENORE
Page 2/3
Operation numbers/damage codes

Op. no.
Operation text
Time
Damage

code
Note
8210R EM Telephone function, poor communication quality/interference noise
WIS-References

Document number
Title
PE82.85-P-2110-97DBA
Wiring diagram for head unit
Cause
PE82.85-P-2110-97IBA
Wiring diagram for head unit
Cause
11-19-2020 10:57 PM

© Copyright Mercedes-Benz AG
Note
CTENORE
Allocation
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