During a phone call, the called party has difficulty understanding/cannot understand the driver, or interference/background noises are audible to the called party during a call. It becomes increasingly difficult to understand as the speed rises.

Voice control does not understand or misunderstands spoken commands.

Note: Please use different approved mobile phones and network providers for the function test.

A. Assembly of microphones (B25/20 or B25/21) in headliner.

B. Dirt inside the microphone housing

c. Wiring between microphone (B25/20 or B25/21) and head unit (A26/17) --> See PE82.85-P-2110-97DBA (example of model series 213)

NOTE: Xentry Diagnostics must always be used to carry out the function test on the microphones (B25/20 and B25/21).

NOTE: As of NTG6, a simple quick test can be carried out. This involves speaking alternately into the microphone directed at the driver and the microphone directed at the front passenger.

• The respective side is highlighted in color on the display to indicate from which side the voice command was detected. An example graphic can be found in the attachment. This function depends on the software version.
• On vehicles with the optional ambient lighting (code 877), the voice commands "... I'm cold" or "... I'm warm" can also be spoken.
  The ambient lighting on the left or right-hand side will accordingly illuminate briefly in "RED" or "BLUE" on the left or right-hand side as a visual indicator.

A. Check assembly of both microphones (B25/20 and B25/21):

1. Remove reading lamp

2. Press finger on rear of microphone (on adhesive tape)

3. Remove microphone cap from the front

4. Remove protruding surplus fabric from microphone cutout in headliner

5. Push microphone from behind until it is firmly pressed into the headliner

6. Maintain pressure and press/clip cap into microphone from the front

7. This procedure must be carried out on both microphones (B25/20 and B25/21)

B. If the problem is still present after the test steps listed above have been performed, check the actual values of the microphones via XENTRY. If necessary, replace both microphones, including their covers.

c. Check wiring of the individual pins between microphone (B25/20 or B25/21) and head unit (A26/17):

1. Connectors X58/3 (microphone electrical connector)

2. Microphone (B25/20 or B25/21)

3. Head unit (A26/17)

NOTE: In some individual cases, it is possible that the wiring to the microphones has been tied back very short. This may impair contacting, resulting in functional interruptions.

Note: One of the fault codes (DTC) listed may be present.