Mercedes-Benz ML320. Service manual - part 241

 

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Mercedes-Benz ML320. Service manual - part 241

 

 

RADIO AND NAVIGATION MODULE, DESIGN - GF82.61-P-4109-03GI

The following is integrated into the radio and navigation module (A2/56) (maximum scope):  

Graphic compatible 5" LCD color display  

Navigation processor with GPS receiver and gyrosensor  

Single CD drive for playing audio CD's (option)  

Navigation CD drive for loading navigation data or for playing audio CD's (optional)  

Telephone unit (optional)  

Radio tuner  

Audio amplifier  

CC player  

The radio and navigation module (A2/56) has the following digital interfaces:  

Digital data bus (D2B)  

K-cable (diagnosis interface) 

Fig. 58: Identifying Radio And Navigation Module (A2/56) Design 

RADIO AND NAVIGATION MODULE, FUNCTION - GF82.61-P-4109-04A 

Models 163, 168, 170, 208, 209, 210 with code 353  

Processing key signals  

The controls on the radio (A2) are read in via I/O ports of the microcontroller and made available to the central 
computer. Depending on the system function the button operations are processed further in the central computer 
or conveyed via the Digital Data Bus (D2B) or interior CAN (CAN B) in the form of a data telegram to the 
system components involved (e.g. CD changer). 

Display  

 

2001 Mercedes-Benz ML320 

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

  

me 

 

The display of the radios (A2) has 197 x 32 pixels. Texts are displayed in 3 lines.

After particular functions are called (e.g. navigation), the bottom line shows a variable inscription for the row of 
buttons underneath (multifunction buttons). As a result the system can be operated very conveniently with a few 
buttons, as the function which is activated when the button is operated, is shown in plain text (e.g. LANG, 
ITEM, DYN, CLOCK etc.). 

Audio signal output  

The audio signals of the various sources (CD, voice output for navigation etc.) are processed by the radio (A2) 
and amplified before output by the vehicle speakers. 

 On models 168, 170, 208 and 210 with the sound system (code 810) the audio signals are finally amplified 

by the amplifier for the sound system (N40/3). For this, the audio source data (low-frequency signals) are 
transmitted to the amplifier for the sound system (N40/3) via separate lines. 

 On models 163 and 209 the final amplification of the audio signal is performed by the sound amplifier 

(A2/13). All the data are transmitted via the D2B. 

Audio mute  

An incoming phone call activates the audio mute function (a separate signal input exists on the radio (A2) for 
this). When the audio mute function is activated, the current audio source (e.g. radio) is muted automatically. 

Navigation processor, GPS control module and gyrosensor  

The navigation processor is the central component of the navigation system. 

It is integrated into the radio (A2) and from the incoming signals continuously calculates the location and once 
the destination is entered calculates the route for navigation. The GPS receiver is integrated into the navigation 
processor. It evaluates the satellite signals and calculates from them the vehicle position in degrees longitude 
and latitude. Various GPS antennae are used to receive these signals depending on the vehicle model: 

Model 163: telephone and GPS roof antenna (A2/49)  

Models 168, 208.3, 210: GPS antenna (A2/49a2)  

Models 170, 208.4: GPS rear antenna (A2/23a2)  

Model 209: GPS antenna (A2/23)  

 Reception from at least 3 satellites is necessary for exact GPS position calculation. A free view of the sky is 

required for this purpose. 

The integrated gyrosensor continuously senses every change in direction of the vehicle. Evaluation of this data 
is accomplished by the navigation processor. 

 Calibration of the gyrosensor is not required.

 

2001 Mercedes-Benz ML320 

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

  

me 

 

DVD drive and DVD  

The DVD drive of the radio (A2) reads data from the navigation DVD inserted and makes this available to the 
navigation processor via the data bus inside the device. 

 Audio CDs can also be played. 

The following are located on the navigation DVD: 

Program data for the navigation computer  

Voice segments for voice output  

Map data.  

A distinction is made between digitized and non-digitized areas within the DVD map area: 

Villages, towns, roads, intersections and their attributes (e.g. one-way streets, no turns etc.) are recorded 
in the digitized map area.  

Included in the non-digitized areas are, for example company/private grounds, farms, small housing 
estates, tracks across fields and areas between villages.  

No data is available here. 

Diagnosis interface (K-line) and fault management of D2B-components  

During operation, the system stores all occurring faults in the nonvolatile memory. It is not possible to output 
the fault via the display of the radio (A2). 

The radio's (A2) fault management also includes the D2B-components connected. For this purpose, each D2B 
component has its own DTC memory. The faults are transmitted from the corresponding components via the 
D2B to the radio (A2) and can then be read out via the diagnosis interface 

RADIO AND NAVIGATION MODULE, FUNCTION - GF82.61-P-4109-04GI 

Processing button actuations  

The control buttons and switches on the function keypad on the radio and navigation module (A2/56) are read 
in via the I/O ports of the microcontroller and transferred to the central processor. Depending on the system 
function the button actuations are processed in the central processor or relayed to the other system components 
via the digital data bus ( D2B ) in form of a data telegram. 

Graphic preparation and image output  

The graphics subsystem handles the preparation and output of the operating displays. The operating displays are 
output internally to the display by the graphic subsystem via the RGB output ( R =red, G =green, B =blue). 

The RGB signal contains information and amplitudes of the three basic colors ed, G reen and lue as well 

 

2001 Mercedes-Benz ML320 

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

  

me 

 

as a synchronization signal. The electronic control in the display unit evaluates the RGB signal and actuates the 
individual pixels line by line according to color and intensity. 

A horizontal synchronization pulse is output at the end of each line. The electronic circuitry of the display unit 
then starts the next line. After reaching the last line on the display, a vertical synchronization pulse is output and 
the electronic circuitry starts again with the first line. 

Audio signal output  

The audio signals from the various sources (CD, voice output for route guidance, ...) are processed by the radio 
and navigation module (A2/ 56) and amplified before output over the vehicle loudspeakers . On vehicles 
with sound system (code 810) final amplification of the audio signals is accomplished by the sound amplifier 
(A2/13)
 . For this purpose audio source data is transmitted to the sound amplifier (A2/13) via the digital data 
bus ( D2B ). 

Diagnosis interface (K bus) and D2B component error management  

During the radio and navigation module (A2/56) mode the system stores all errors which occur in the non-
volatile memory. These errors can then be read out on the diagnostic interface (K bus) with Star diagnosis . 
Output of the errors on the display unit is not possible. 

Error management also includes components connected to the digital data bus ( D2B ). 

Each D2B component has its own DTC memory . The errors are transmitted to the radio and navigation 
module (A2/56) via the digital data bus (D2B) on request by STAR diagnosis and can then be read out with the 
diagnostic interface. 

Navigation processor and GPS control module  

The navigation processor is the central component of the radio and navigation module (A2/56) . It is 
integrated into the radio and navigation module (A2/56) and calculates the location and vehicle route from the 
incoming signals after entering the route. 

The GPS control module is a part of the navigation processor. It evaluates the satellite signals distributed by 
the CTEL/GPS roof antenna (A2/49) and the CTEL and GPS antenna splitter (A2/57) and calculates with 
this information the vehicle position. 

CD-ROM and CD drive  

With the aid of the navigation CD drive it is possible to read data from the special navigation CD or play 
audio CD's or play . 

The following is stored on the navigation CD-ROM : 

Program data for execution in navigation processor  

Voice data for voice output  

 

2001 Mercedes-Benz ML320 

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

  

me 

 

 

 

 

 

 

 

 

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