COMAND(R) - Intermittent Sound Function

COMAND: OCCASIONALLY NO SOUND AFTER ENGINE START; OCCASIONALLY SOUND FAILURE WHEN DRIVING

Topic Number LI82.62-P-047460

Version 1

Design Group 82.62 Loudspeakers, amplifiers, antennas

Date 07-23-2009

Validity Model 216, 221 without code 810 (sound system)
Affected VIN ranges: as of 216.###1A018300, as of 221.###1A222121

Reason for change

Reason for block

Complaint:

1. Occasionally no sound from speakers, but the COMAND (A40/3) can be operated.

2. Occasionally no sound from speakers after engine start, sound can be heard again after frequency change.

3. Sound occasionally fails, no frequency band visible in the COMAND display (A40/8).

4. Occasionally no sound after station change, no station visible in the COMAND display (A40/8).

5. No sound from speakers after driving for approx. 2 hours.

Note:
All functions are available again after ignition OFF/ON.

Cause:

Software fault in audio tuner control unit (N93/1).

Due to fluctuations in the on-board electrical system, the audio tuner control unit (N93/1) can enter a critical voltage range and then fail as a result.

Note:
The fault only occurs in combination with the audio tuner control unit (N93/1) with the part number A 221 820 52 89 (SW 36/07 and HW 32/05).

Please do not replace any parts at this time.





Symptoms





Work units





Validity