GF82.10-P-2009FLA Headlamp Control, Function
GF82.10-P-2009FLA Headlamp Control, Function
MODEL 212.0 /2
- with CODE (615) Bi-xenon headlamp unit with integrated curve illumination
- with CODE (616) Bi-xenon headlamp unit with integrated asymmetric curve illumination
- with CODE (621) Intelligent Light System (left-hand traffic)
- with CODE (622) Intelligent Light System (right-hand traffic)
Function requirements, general
^ No overvoltage or undervoltage (operating voltage range U greater than or equal to 7 17.5 V)
Driving lights actuation, general
Driving lights actuation includes all functions which serve the optimum illumination of the road while driving.
During driving lights actuation, the standing lights actuation is active; this is described in the "Standing/parking lights actuation, function" document.
The driving lights actuation encompasses the following subfunctions:
^ Function sequence for low beam actuation
^ Function sequence for high beam actuation
^ Function sequence for daytime running lights actuation
^ Function sequence for auto on/off headlamps
^ Function sequence for automatic headlamp range adjustment (HRA [LWR])
The driving lights are actuated corresponding to the position of the exterior lights switch (S1). The status of the exterior lights switch is read by the front SAM control unit with fuse and relay module (N10/1) in model 212.0 up to 30.11.09 except model 212.077 via instrument panel LIN (LIN 1) and in model 212.077, 212.2 and model 212.0 as of 1.12.09) directly.
Additional low beams actuation function requirements
^ Circuit 15 ON
The electronic ignition lock control unit (N73) sends the status of circuit 15 to the front SAM control unit over the interior CAN (CAN B).
Function sequence for low beam actuation
Turning the exterior lights switch to the "Manual driving lights" position requests actuation of the low beams.
The front SAM control unit reads in the status of the exterior lights switch and forwards the "low beams ON" request using a voltage signal (circuit 56b) straight to the left xenon light control unit (E1n1) at the left front lamp unit (E1) and to the right xenon light control unit (E2n1) at the right front lamp unit (E2). The front SAM control unit also sends the "low beams indicator lamp ON" request over the interior CAN to the instrument cluster (A1).
The left xenon light control unit actuates the left xenon bulb with integral ignition module (E1e10) and the right xenon light control unit actuates the right xenon bulb with integral ignition module (E2e10). The instrument cluster actuates the low beams indicator lamp (A1e67).
Additional function requirements for high beam actuation
^ For high beams function: Circuit 15 and low beams On
^ For headlamp flasher function: Circuit 15R On
^ Adaptive high beams function (with code (608) Adaptive Highbeam Assist) not active
The electronic ignition lock control unit sends the status of circuit 15 to the front SAM control unit over the interior CAN.
Function sequence for high beam actuation
The high beams actuation is comprised of the following subfunctions:
^ Function sequence for high beams
^ Function sequence for headlamp flasher
Function sequence for high beams
High beam actuation is requested by pushing the combination switch (S4) forward.
The steering column tube module control unit (N80) directly reads in the position of the combination switch and transmits it to the front SAM control unit via the chassis CAN (CAN E).
The front SAM control unit receives the switch position of the combination switch and sends this over the front end CAN (CAN G) to the xenon light control unit. The front SAM control unit also generates the "high beams ON" request and sends this over the interior CAN to the instrument cluster. The left xenon light control unit actuates the left light distribution actuator motor (E1m3) and the right xenon light control unit actuates the right light distribution actuator motor (E2m3) in each case over the Local Interconnect Network (LIN) (headlamp internal).
The rollers which partially cover up the xenon bulb's light cone, are turned thereby uncovering the entire light beam to illuminate the traffic lane.
The instrument cluster actuates the high beams indicator lamp (A1e3).
Function sequence for headlamp flasher
The function sequence and signal path for the headlamp flasher function correspond to that of the high beam function.
However, to request the headlamp flasher function, the combination switch must be pulled backward. If the combination switch is pulled back and held, the high beam actuation is active for maximum t = 30 s. The permanently present request is then interpreted as a "stuck combination switch".
Since no separate high beams are installed to implement the headlamp flasher function, the xenon bulbs must be illuminated when low beams actuation is not active.
Additional function requirements for daytime running lights actuation
^ "Daytime running lights:" function activated in "Settings", "Light" menu in instrument cluster (except vehicles with code (460) Canada version)
^ "Engine running" or "drivetrain ready" signal set or vehicle speed v > 3 km/h
^ Exterior lights switch in position:
- Exterior lights Off "0" or
- "Left parking lights" or "Right parking lights" (model 212.0 up to 30.11.09 except model 212.077) or
- Auto on/off headlamps "A"
Function sequence for daytime running lights actuation
The instrument cluster sends the request "Daytime running lights On" depending on the country coding or if the daytime running lights request was manually activated in the menu "Settings", "Light" via interior CAN.
The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) sends the "engine running" or "drivetrain ready" signal over the chassis CAN.
The instrument cluster sends the vehicle speed over the interior CAN.
The front SAM control unit reads in all relevant information, evaluates it and for vehicles without code (498) Japan version (up to 31.5.10) and without code (835) South Korea version (up to 28.2.11) it directly actuates the left daytime running lights headlamp (E1/3) and the right daytime running lights headlamp (E2/3).
In vehicles with code (498) Japan version, the front SAM control unit activates the low beams actuation.
The daytime running lights headlamps installed as of 1.6.10 are actuated as position lamps.
In vehicles with code (835) South Korea version, the daytime running lights headlamps are installed, but not actuated until 1.3.11.
When dark, the front SAM control unit actuates the daytime running lights headlamps with reduced power (night design circuit) and activates the low beam actuation.
The ambient brightness is sensed by the rain/light sensor (B38/2).
The front SAM control unit reads in the data of the rain/light sensor via wiper/inside rearview mirror LIN (LIN 2).
The daytime running lights actuation is deactivated as soon as the exterior lights switch is turned to position "Standing lights", "Manual driving lights" or "Left parking light" or "Right parking light" (model 212.077, 212.2 and model 212.0 as of 1.12.09).
In vehicles with code (460) Canada version, the daytime running lights actuation is switched off after expiration of a period of t = 3 min when the vehicle is standing still. When the vehicle then starts to move again, the front SAM control unit automatically activates daytime running lights actuation.
The daytime running lights have a higher priority than the auto on/off headlamps.
In countries with legal daytime running light requirements, only the headlamp flasher is permissible but not the high beams.
The high beams are permissible only when the high beams are manually switched on via the exterior lights switch (without code (460) Canada version and without code (494) USA version).
Additional function requirements for auto on/off headlamps
^ "Engine running" or "drivetrain ready" signal set or vehicle speed v > 3 km/h
^ Exterior lights switch in position "A" or "0" (model 212.0 up to 30.11.09 except model 212.077) (can be coded)
^ Rain/light sensor signals "Darkness detected"
Function sequence for auto on/off headlamps
The auto on/off headlamps function is no more than a comfort function and does not exempt the driver from following the rules in the road traffic regulations.
The CDI control unit or the ME-SFI [ME] control unit sends the "engine running" signal or the "drivetrain operational" signal over the chassis CAN to the front SAM control unit.
The instrument cluster sends the vehicle speed to the front SAM control unit over the interior CAN.
The front SAM control unit reads in the status of the exterior lights switch over the instrument panel LIN or directly and the rain/light sensor data over the wiper/inside rearview mirror LIN.
With the auto on/off headlamps, the low beams are automatically switched on or off.
This occurs depending on the ambient brightness or depending on the activities of the wiper system:
^ Function sequence for auto on/off headlamps over rain/ light sensor
^ Function sequence for auto on/off headlamps via wiper activities
Function sequence for auto on/off headlamps over rain/light sensor
Ambient brightness is assessed by the rain/light sensor. The front SAM control unit reads in the data of the rain/light sensor via wiper/inside rearview mirror LIN and activates the low beams actuation if darkness is recognized.
Function sequence for auto on/off headlamps via wiper activities
If the low beams are switched on or off due to the activities of the wiper system, one refers to wiper, rain or adverse weather light.
The front SAM control unit controls the wiper system and evaluates the data of the rain/light sensor or the wipe request via the combination switch for this.
If the windshield wiper system is activated for t = greater than or equal to 20 s with a wipe cycle time of t < 6 s, the front SAM control unit activates low beam actuation. If there are no wipe cycles for t greater than or equal to 60 s, low beams actuation is deactivated.
Auto on/off headlamps switch-off conditions:
In the event of rain/light sensor failure, the auto on/off headlamps are not deactivated until the engine is switched off.
When the vehicle is being driven through a tunnel and if the wiper start suppression function is active, the auto on/off headlamps function remains switched on.
If the wiper start-up suppression function is canceled, the auto on/ off headlamps remain active for an additional t = 60 s.
Additional function requirements for automatic headlamp range adjustment
^ "Engine running" or "drive train operational" signal on
^ Driving lights On (low beam/high beam)
Function sequence for automatic HRA [LWR]
The automatic HRA [LWR] permits the correction of the headlamp range of the vehicle headlamps as a function of the load or the vehicle pitch motions induced by the vehicle dynamics.
The CDI control unit or the ME-SFI [ME] control unit sends the set "Engine running" or "Drivetrain ready" signal over the chassis CAN, front SAM control unit and the front end CAN to the xenon light control units.
In order to determine the current vehicle level, the left xenon light control unit in vehicles without code (488) Steel/air suspension and without code (489) AIRmatic (air suspension with continuous adjustment damping) reads in the signals of the left rear level sensor (B22/7) and the left front level sensor (B22/8) directly.
In vehicles with code (488) Steel/air suspension or code (489) AIRmatic (air suspension with continuously adjustable damping), the AIRmatic control unit (N51/3) sends all data required for evaluation of the vehicle level via chassis CAN, front SAM control unit and front end CAN to the xenon light control units. To this end, the AIRmatic control unit also evaluates the data from the right front level sensor (B22/9) and the right rear level sensor (B22/10).
Zero-point programming is performed at the end of production to compensate for suspension tolerances.
With successful programming, visual feedback occurs through the movement of the headlamp units "center-down-up-center".
If the vehicle is moving at a constant speed, the automatic headlamp range adjustment system operates in "static mode" at a slow adjustment rate.
When the vehicle is accelerated, the "dynamic mode" is activated and the reaction time of the headlamp range adjustment is reduced sharply.
The "dynamic mode" is activated depending on the amount of speed change and additional signals such as the brake pedal and the accelerator pedal positions.
When the vehicle is standing automatic headlamp range adjustment is accomplished in the "dynamic mode".
Information on wheel speeds and wheel rotation directions, as indicators of vehicle speed, is sent by the Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS, except model 212.074/077/274/277) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS or model 212.074/077/274/277) over the chassis CAN, front SAM control unit and the front end CAN to the xenon light control units.
Both xenon light control units receive this information and communicate with each other via front end CAN.
The xenon light control units operate in a master/slave combination, whereby the left xenon light control unit acts as the master and synchronizes the right xenon light control unit.
The left xenon light control unit actuates the left headlamp range adjustment actuator motor (E1m1) accordingly and the right xenon light control unit actuates the right headlamp range adjustment actuator motor (E2m1) via the relevant Local Interconnect Network (LIN) (headlamp-internal).
