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Home >> Mercedes Benz >> 2021 >> GT 43 AMG >> Repair and Diagnosis >> Accessories & Equipment >> Collision/Avoidance >> Electrical System, Equipment & Instruments (2 Of 4) -- 290 Chassis >> Basic Knowledge >> Head-Up Display, Function - GF54.30-P-3048FR

Head-Up Display, Function - GF54.30-P-3048FR

Model 257, 290 

up to model year 2021 

with code 463 (Head-up display) 

Function requirements in general 

Head-up display, general 

The head-up display projects driving-relevant information (e.g. speed, navigation information) onto the windshield and into the field of view of the driver. This information is displayed redundantly together with the information shown in the instrument cluster.

The viewer sees the display floating just above the engine hood of the vehicle at the level of front edge of the engine hood. The display of the head-up display can be adapted to the size of the driver by means of an adjustment mechanism (head motion box). The large distance between the display and the eye of the driver (approx. s = 2 meters) ensures low-fatigue and comfortable viewing of the displayed information.

IMPORTANT

Model 257, 290

up to model year 2021

with code 357 (Map navigation)

with code 463 (Head-up display)

Model 257, 290

up to model year 2021

with code 463 (Head-up display)

with code 531 (COMAND APS)

The head-up display continuously projects navigation information irrespective of the display on the instrument cluster. For this purpose, the head unit (A26/17) sends corresponding data over the user interface CAN to the head-up display.

The head-up display function includes the following subfunctions:

Function sequence for head-up display ON/OFF 

By pressing the head-up display button (S6/1s6) in the driver side instrument panel button group (S6/1), the head-up display can be switched on or off.

The front SAM control unit (N10/6) reads in the status of the head-up display button over the instrument panel LIN (LIN 1) and sends this over the interior CAN (CAN B), electronic ignition lock control unit and the user interface CAN to the instrument cluster (A1). The instrument cluster activates the head-up display via the user interface CAN, processes the visual information to be displayed, and sends this over the high-speed video link line (HSVL) to the head-up display.

IMPORTANT To compensate for dimensional tolerances, the instrument cluster contains a so-called "warping engine" (visual processing) in order to artificially equalize visual information in advance. This ensures that an equalized, straight image appears in the driver's field of vision. The head-up display is supplied with its own "warping matrix" which must be transferred to the instrument cluster.

When exchanging the instrument cluster or the head-up display, the "warping matrix" must be transferred to the new instrument cluster. When exchanging the windshield, the head-up display must be recalibrated via the "workshop menu" in the instrument cluster or on a test stand.

Function sequence for adjusting head-up display 

In the instrument cluster, the "Head up display" submenu can be used to make individual settings for the head-up display with regard to position (relative value), brightness (relative value) and display contents.

This is done using the instrument cluster multifunction steering wheel button group (S163/1). The steering wheel electronics (N135) reads in the signals from the multifunction steering wheel button group directly and sends them over the steering wheel CAN (CAN LR) to the steering column tube module control unit (N80). The steering column tube module control unit sends the signals from the multifunction steering wheel button group via the chassis FlexRay (Flex E), electronic ignition lock control unit and user interface CAN to the instrument cluster. The instrument cluster evaluates these signals and transmits appropriate requirements via the user interface CAN to the head-up display.

Function sequence for automatic brightness control 

The brightness of the head-up display is adjusted automatically to the ambient brightness. This guarantees readability both during the day and at night. In case of an unfavorable position of the sun (sun low on the horizon directly in front of the vehicle) it may cause the display to be unreadable. In case of wet road surfaces, the background of the head-up display can become so bright that the display is barely visible.

The head-up display light sensor (B38/2b4) in the rain/light sensor with additional functions (B38/2) determines the current road surface brightness. The rain/light sensor with additional functions reads in the signals of the head-up display directly and transmits these via the rain/light sensor LIN (LIN B16), front SAM control unit, interior CAN, electronic ignition lock control unit and user interface CAN to the head-up display. Based on these data, the head-up display adjusts its brightness dynamically to the respective conditions.

Function sequence for memory function (with CODE 275 (Memory package)) 

The position of the "head motion box" can be saved and called up together with the driver's seat position. The request to save or take the memory position is transmitted by the driver seat control unit (N32/1) via the interior CAN, electronic ignition lock control unit and user interface CAN to the head-up display.

IMPORTANT Detailed information on saving and calling up memory positions is contained in a separate document.

  Electrical function schematic for heads-up display   PE54.30-P-2065-97XBA
  Overview of system components, instrument cluster (IC) component description   GF54.30-P-9996FR