Modular Control System (MCS) Speed-Dependent Volume Control Malfunction In; Vehicles Equipped With Sound Amplifier (82.60/192C)

Publication date: 2006-10-02
Reference number: 82.60/192C
Supersedes refnos: 82.60/192A, 82.60/192B

MODULAR CONTROL SYSTEM (MCS) SPEED-DEPENDENT VOLUME CONTROL MALFUNCTION IN; VEHICLES EQUIPPED WITH SOUND AMPLIFIER

TECHNICAL SERVICE BULLETIN

Reference Number(s): T-B-82.60/192C, Date of Issue: October 2, 2006

MERCEDES-BENZ:	Model 163.154/174; Model 163.157/175; As of Model Year 2002
GROUP:	82 - Electrical System - Body

Superceded Bulletin(s): T-B-82.60/192B, Date of Issue: September 14, 2004

SUBJECT

Model 163.154/174, as of VIN A289560

Model 163.157/175

As of Model Year 2002, Equipped with BOSE Sound Amplifier Option Code 810

Modular Control System (MCS) Speed-Dependent Volume Control Malfunction in Vehicles Equipped with Sound Amplifier

SERVICE INFORMATION

If you receive customer reports in the above model vehicles of unexpected volume fluctuation or speed dependent volume adjustment not functioning, this may be due to the Sound Amplifier (A2/13) not coded correctly to handle the wheel speed signal or due to a malfunction in the Sound Amplifier microphone (B25/6). To resolve, follow the procedure outlined below.

A. CHECK THE MCS AND BOSE SOUND AMPLIFIER

Connect DAS -> Select the vehicle model -> control units -> information and communication -> D2B-COMAND, MCS or Audio -> control unit adaptations -> read coding and change if necessary -> Radio parameters -> vehicle response volume, set the vehicle's speed-dependent volume control to "OFF" -> F3 -> F3 -> select "yes" to carry over the coding the MCS -> F2 to reset the MCS. If the error still exists, proceed to step 2.
Read out any Diagnostic Trouble Codes. Check for DTC N1260 (Sound Amplifier Faulty). If the DTC is stored, replace the Sound Amplifier. Refer to WIS document AR82.62-P-7720GH. If error still exists, proceed to step 3.
Visually check the part number and "Q-Level" of the Sound Amplifier. Ensure the vehicle is equipped with: Sound Amplifier part number A163 820 27 89 or later and Q-5 or later version.

NOTE: As of MY 2002, the speed-dependent volume is controlled by the BOSE Sound Amplifier.

B. CHECK THE SOUND AMPLIFIER MICROPHONE

Check the Sound Amplifier Microphone (Fig 1, B25/6). Reference WIS Document AR82.62-P-1110GH.
If the microphone is not functioning correctly, replace it in accordance to WIS Document AR82.62-P7700GH (Fig 1).
NOTE: As you remove the Microphone, insure that the wiring harness is not damaged.
After assembly of new microphone, re-check per step 1.

Fig 1: Sound Amplifier Microphone

PARTS INFORMATION

Qty.	Part Name	Part Number
1	Microphone	A163 820 10 35
1	Sound Amplifier, BOSE - Q5 or higher	A163 820 27 89