Mercedes-Benz ML320. Service manual - part 233

Navigation system - additional unit with CODE (818b) Single CD player - additional unit with CODE 
(491) U.S. version  

It is necessary to distinguish between audio and service sources on the radio and navigation module (A2/56) : 



Audio sources are: 



Radio  



CD player  



CC player  



CD changer (code 819a)  



Service sources include: 



Voice output on navigation  



telephone  

Signal editing required for volume and tone settings is accomplished by the audio component integrated into 
the radio and navigation module (A2/56)  

If the vehicle is additionally equipped with a sound system (code 810), the sound amplifier (A2/13) ensures 
final audio signal amplification. 



Volume setting 

By turning the volume knob the volume of the corresponding mode changes. 



Tone setting 

The tone settings as well as the general brightness adjustment of the display can be reached by pressing 
the multifunction key" ADJ ". If the multifunction key" ADJ " is pressed for longer than 2 s all tone 
settings of all modes jump back to the center position. This is confirmed by a short peep tone. The 
adjustment possibilities for treble/bass, balance and fader are summarized in one display. 

They can be selected by actuating the multifunction keys " " and " ". The corresponding setting can be 
changed by actuating the multifunction keys"- " and "+ " or "L ", "R ", "F " and "R ". 

 These settings can also be made with the "joystick " in an analogous manner. When the headlamps are 

switched on the brightness setting of the display can be reached by pressing the multifunction key" BRT " in the 
tone setting menu. Here it is possible to select between " bright " and "dark ". Simultaneously pressing the 
multifunction keys " - " and "+ " or "L " and "R " or "F " and "R " resets the corresponding setting in the 
current mode to the center position 

 Tone setting is not possible in the telephone or navigation mode. The tone or brightness setting can be exited 

by pressing the multifunction key EXIT ". 

 

Voice output, function

 

GF82.85-P-3001GI

 

2001 Mercedes-Benz ML320 

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

  

me 

 

AUDIO 30 APS, LOCATION OF COMPONENTS - GF82.61-P-0002-01D 

Fig. 39: Identifying Audio 30 APS Components Location 

The FM/AM antennas are located in the rear window . 

AUDIO 30 APS BLOCK DIAGRAM - GF82.61-P-0002-02D 

Model 163 with code 353  

 

Radio and navigation 
module, location/purpose/ 
design/function

 

GF82.61-P-4109GI

 

2001 Mercedes-Benz ML320 

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

  

me 

 

Fig. 40: Identifying Audio 30 APS Block Diagram 

AUDIO 30 APS OPERATING INSTRUCTIONS - GF82.61-P-0002-03A 

Models 163, 168, 170, 208, 210 with code 353  

Controls on radio and navigation unit (A2/56) with explanations of primary functions.  

Fig. 41: Identifying Radio And Navigation Unit Controls

 

2001 Mercedes-Benz ML320 

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

  

me 

 

Activating anti-theft alarm  

During initial operation of the radio and navigation unit (A2/56) it is necessary to activate the anti-theft 
alarm with the aid of the hand-held tester. 

 After activation has been accomplished, deactivation is no longer possible. 

Only after activation is it necessary to enter a 5-digit code after interruption of the power supply. When entering 
the code observe: 



After the code has been entered incorrectly three times the message "Wait" appears. The radio and 
navigation unit (A2/56) is then disabled for ten minutes. ?  



Following the next three incorrect entries operation is not possible for ten minutes again. ?  



Then after an additional 3 incorrect entries the unit is disabled for 1 hour in each case.  

 The waiting time expires only with the radio and navigation unit (A2/56) switched on. 

Inserting and ejecting CD  

CDs can be inserted and ejected (audio or navigation CD) in all operating states. After pressing the "eject 
button" a CD already inserted is ejected by a motor. If the CD is not removed within approx. 14 seconds, it is 
pulled back in automatically. 

After inserting a CD it is necessary to push it a slight distance into the CD opening; it is then pulled in the rest 
of the way automatically. 

 When a navigation CD is inserted the menu for entering destination is activated automatically. However, 

this applies only when the system has previously requested that the navigation CD be inserted. 

 The eject button for the CD drive also functions when the radio and navigation unit (A2/56) is in the "code 

wait state". This means that a CD can be removed in spite of the request to enter the anti-theft code. 

Glossary 

Abbreviation

Meaning

Explanation

AM

A mplitude M odulation

The amplitude of the carrier 
frequency is modulated with the 
signal (e.g. LW, MW and SW 
radio)

CD

C ompact D isc

Storage medium for all types of 
data (music, programs,).

D2B

D igital D ata B us

Optical bus system for transfer of 
data via fiber optic cable.

FM

F requency M odulation

The signal is transmitted by 
changing the frequency of the 
carrier (e.g. FM radio)

 

2001 Mercedes-Benz ML320 

1998-2005 ACCESSORIES & BODY, CAB Electrical System - Body - 163 Chassis

  

me