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Attention Assist, Function - GF54.30-P-0009GN

MODEL 166 as of model year 2016 

MODEL 292 

Block diagram, except model 166.063 

G11969340

Block diagram, model 166.063 

G11969341

Function requirements, general 

IMPORTANT The CDI control unit or ME-SFI [ME] control unit sends the signal "Engine running" or "Drive train operational" to the Electronic Stability Program control unit via chassis CAN 1.

IMPORTANT The ME-SFI [ME] control unit sends the "Engine running" or "Drive train operational" signal via the engine CAN, powertrain control unit, and chassis CAN 1 to the Electronic Stability Program control unit.

Attention Assist, general 

The attention assistance system is integrated in the Electronic Stability Program control unit. By evaluating steering patterns any onset of driver fatigue (e.g. on long monotonous journeys on freeways and highways) can be detected. The steering patterns are evaluated within a vehicle speed range of v = 60 to 200 km/h. If any appropriate signs indicating fatigue or increasing lack of attention by the driver are recognized, the driver is prompted to take a break by means of visual and acoustic warnings.

IMPORTANT Development of this software is based on experience gathered with test persons, whose different handling characteristics at night and day times were evaluated.

Function sequence for Attention Assist 

The attention assistance system can be switched on or switched off by the driver in the "Assist." menu at the "Attention Asst." menu level of the instrument cluster.

IMPORTANT The driver handling characteristics are also analyzed when the Attention Assist is switched off. If the Attention Assist system is switched on by the driver during a journey, the entire journey from the start is taken into consideration.

The activated attention assistance system is rendered passive by the system when system constraints are overshot or undershot (e.g. vehicle speed < 60 or > 200 km/h). In the passive state, an "Attention Level" (bar display, 5-stage) is not calculated and warning messages are suppressed.

IMPORTANT If the attention assistance system is switched to passive, the bar display changes and the "System passive" message is output on the multifunction display of the instrument cluster in addition to the driving time since the start of driving.

The instrument cluster sends the status of the attention assistance system via the chassis CAN 2, electronic ignition lock control unit, and chassis CAN 1 to the Electronic Stability Program control unit.

The driver can select the following operating modes:

In "Sensitive" operating mode, the Attention Assist reacts more sensitively and issues warning messages sooner than in "Standard" operating mode.

In the "Off" operating mode, no additional display is shown and the output of warnings is suppressed. "System switched off" is displayed instead.

If the "Off" operating mode is selected, this is indicated by a coffee cup symbol and also the text "OFF" below in the multifunction display of the instrument cluster when the engine is running or the drive train is operational. If the Attention Assist is in "Standard" or "Sensitive" operating mode, the coffee cup symbol is not displayed.

IMPORTANT "Last-turned-on mode":

If the "Standard" or "Sensitive" operating mode was selected before an ignition cycle, this mode is selected again after the next ignition cycle. If the attention assistance system is switched off while driving (operating mode "Off"), the operating mode that was selected before switching off is automatically selected after the next ignition cycle.

The driver can call up the following additional information via the "Info page" in the "Attention Asst." menu level of the instrument cluster:

Display of messages in relation to 

G11969342

At the start of the journey the Electronic Stability Program control unit uses an algorithm to determine the driver's individual warning threshold. This is the driving time and the time of day. Up to 5 bars are highlighted in color in the "Attention Level" display.

If the number of indicators for lack of attention or fatigue goes up or in the event of a longer driving distance, the number of bars is reduced as is their colored highlighting. An increase in awareness ("Attention Level") is also possible.

Colored highlighting is implemented as follows:

If the warning threshold has been exceeded, the Electronic Stability Program control unit sends the request to output a warning via the chassis CAN 1, electronic ignition lock control unit, and chassis CAN 2 to the instrument cluster, and on vehicles with CODE 531 (COMAND APS) or CODE 522 (Audio 20 radio), to the COMAND controller unit (with CODE 531 (COMAND APS)), where it is evaluated.

The warning message "Attention Assist: Pause!" is then displayed on the multifunction display and the driving time since the last break is displayed. An acoustic warning is also issued via the warning buzzer in the instrument cluster. The instrument cluster actuates the warning buzzer directly.

The warning message can be acknowledged using the OK button in the left multifunction steering wheel button group. The steering wheel electronics directly read in the status of the O. K. button and send it via the steering LIN, steering column tube module control unit, chassis CAN 1, electronic ignition lock control unit, and chassis CAN 2 to the instrument cluster. The steering column tube module control unit also transmits the status of the OK button via chassis CAN 1 to the Electronic Stability Program control unit.

IMPORTANT A renewed warning message is issued at the earliest after expiry of t = 15 minutes.

Vehicles with CODE 531 (COMAND APS):

If the warning threshold is exceeded, in addition to the warning message, the nearest rest facilities are displayed to the driver on the Audio/COMAND display. In the process, the rest area icon appears irrespective of whether route guidance is activated. When searching for rest areas, all categories of rest area and parking facility along freeway-type roads (roads with defined entrances and exits) are offered. The display of suitable stops can be switched off using the "Messages" menu on the Audio/COMAND display. The system also remains switched off after an ignition cycle.

The Electronic Stability Program control unit sends the request to issue a warning message via the chassis CAN 1, electronic ignition lock control unit, and interior CAN to the COMAND controller unit (with CODE 531 (COMAND APS)). The COMAND controller unit (with CODE 531 (COMAND APS)) uses the GPS signals and navigation data to determine suitable rest facilities. The COMAND controller unit (with CODE 531 (COMAND APS)) actuates the Audio/COMAND display via the telematics CAN and sends the corresponding video signals via the LVDS line.

Essentially, the following influencing factors are evaluated:

Time of day:

The time of day is also defined by the current time. The instrument cluster sends this to the Electronic Stability Program control unit via chassis CAN 2, electronic ignition lock control unit and chassis CAN 1.

The received time is checked for plausibility by means of evaluating the ambient brightness. The ambient brightness is detected by the light sensor. The rain/light sensor with additional functions reads in the signals of the light sensor directly, evaluates them and transmits information about the ambient brightness (dimness level) via the rain/light sensor-LIN, the SAM control unit, the interior CAN, the electronic ignition lock control unit and the chassis CAN 1 to the Electronic Stability Program control unit.

IMPORTANT If there is a transition between dusk and dawn at an implausible time, an entry is made in the ESP control unit® diagnostic memory.

Driving time:

The driving time is determined by the Electronic Stability Program control unit.

Steering movements:

Steering movements are recorded by the steering wheel angle sensor. The steering column tube module control unit reads in the signals of the steering wheel angle sensor directly and transmits information about the steering wheel angle and the steering wheel velocity to the Electronic Stability Program control unit via chassis CAN 1.

Vehicle speed:

The vehicle speed is calculated by the Electronic Stability Program control unit using the wheel speed.

Vehicle longitudinal/lateral acceleration and yaw rate:

Information about the vehicle's longitudinal and lateral acceleration and the yaw rate is recorded by the turn rate sensor for lateral and longitudinal acceleration. The turn rate sensor for lateral and longitudinal acceleration sends the corresponding values via the vehicle dynamics CAN to the Electronic Stability Program control unit.

Control interventions:

Control interventions at one of the following components disable the detection of steering patterns:

The audio system is operated via the Audio/COMAND control panel or via the touchpad (with CODE 531 (COMAND APS)). The control interventions at the Audio/COMAND control panel are received via the telematics CAN from the radio (with CODE 505 (Radio 20 NTG5 non-navigation-capable), with CODE 522 (Audio 20 radio)), the control interventions at the touchpad (with CODE 531 (COMAND APS)) are received from the COMAND controller unit (with CODE 531 (COMAND APS)). The radio (with CODE 505 (Radio 20 NTG5 non-navigation-capable), with CODE 522 (Audio 20 radio)) or the COMAND controller unit (with CODE 531 (COMAND APS)) send information about control interventions at the audio system via interior CAN, electronic ignition lock control unit and chassis CAN 1 to the Electronic Stability Program control unit.

The steering column tube module control unit sends information about control interventions at the CRUISE CONTROL lever, steering column adjustment switch (with CODE 275 (Memory package)), combination switch and multifunction steering wheel button group to the Electronic Stability Program control unit via chassis CAN 1.

IMPORTANT The steering wheel electronics read in the control interventions on the multifunction steering wheel button groups directly and transmit them to the steering column tube module control unit over the steering LIN.

A warning is suppressed under the following conditions as no inferences about the attentiveness of the driver can be drawn from the driving behavior:

Also valid is the following function information which can lead to possible function complaints:

  1. No warning issued because driving time too short in active vehicle speed range:

    The attention assistance system analyzes development of the handling characteristics. At the start of the journey the individual handling characteristic is classified. If the handling characteristic changes permanently a warning is issued. If the driving time within the active range (v_=_60_to_200_km/h) is too short, a warning is not issued.

  2. No warning because of restrictions associated with the system limits:

    The handling characteristics cannot be evaluated in the active vehicle speed range (v_=_60_to_200 km/h) either if certain factors occur such as frequent lane changing, twisty roads, frequent control interventions, surface undulations, crosswinds or a dynamic driving style.

  3. Personal driving behavior:

    The attention assistance system detects changes in driving behavior.

    These changes cannot always be explained as fatigue or increasing inattentiveness, rather they can also be caused by peculiarities in steering behavior. Certain types of driver present particular challenges for attention assistance systems, e.g. drivers with extremely smooth or extremely active steering behavior.

  4. Influence of the time on the sensitivity of the Attention Assist:

    The Attention Assist reacts in accordance with the human bio-rhythm depending on the time (e.g. the mid-day low). These results are determined representatively, but they may also differ on an individual basis.

  5. Influence of driving time on the sensitivity of the Attention Assist:

    As the length of driving time without a break increases, the sensitivity of the Attention Assist function also increases. The weighting of the driving time is based on surveys and correspond to the average fatigue characteristics.

  6. Warning because of distraction or mild fatigue:

    Attention Assist can not only warn in the event of fatigue, it can also warn when a change in handling characteristics occurs, e.g. where the driver is greatly distracted. Therefore, a warning issued because of increasing inattentiveness is also to be deemed correct. The subjective fatigue sensitivity and the objective assessment variable determined by the Attention Assist are different.

  7. Change in steering ability through other factors:

    Next to fatigue or increasing inattentiveness other factors can also significantly change the steering ability, and influence the objective assessment variables as determined by the Attention Assist, e.g. increasingly slippery road surface, worsening visibility, narrowing roadway, worsening roadway.

  8. Influence of Steer Assist (with CODE 266 (DISTRONIC PLUS with Steer Assist and Stop & Go Pilot)) on the steering pattern evaluation:

    If the steering assistance system is active, it is unclear whether steering movements have been made by the driver or by the electric power steering.

  9. Influence of "Sensitive" setting:

    When the "Sensitive" setting is selected, the sensitivity is increased. The awareness determined by the attention assistance system ("Attention Level") is adapted accordingly and warnings are output earlier.

  Attention Assist electrical function schematic   PE54.71-P-2054-97NBA
  Overview of system components for driver assistance systems   GF54.00-P-9998GN
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