Component Description For Front Reversible Emergency Tensioning Retractors - GF91.40-P-4020GW

Model 463 (except 463.342)

as of model year 2019

View of vehicle with reversible belt tensioners at front left and right

Fig 1: Front Reversible Emergency Tensioning Retractors Components Location - Model 463 (Except 463.342) As Of Model Year 2019

Courtesy of MERCEDES-BENZ USA

Location

The reversible emergency tensioning retractors are located at the bottom of the respective B-pillar.

Tasks

The reversible emergency tensioning retractors have the task of tensioning the seat belt of the driver or front passenger seat in certain hazardous situations by actuating an integrated actuator motor. Securing the vehicle occupants in the seat in a more optimal fashion minimizes the consequences of a potentially impending accident. If the seat belt adjustment function is active, the seat belt slack is additionally reduced when the seat belt is fastened. The tasks are subdivided as follows:

Reading in of signals
Evaluation of input factors
Transmitting signals

Reading in of signals

The following signals, among others, are read in via the user interface CAN (CAN HMI):

Status of driver seat belt buckle switch (S68/3)
Status of front passenger seat belt buckle switch (S68/4)
Crash signal
PRE-SAFE® status
PRE-SAFE® stage
Status of seat belt adjustment function

Evaluation of input factors

The read-in input factors are evaluated by the integrated microprocessor whereupon the integrated components are actuated and the CAN signals issued.

Transmitting signals

The reversible emergency tensioning retractors send e.g. the request to display a fault message via the user interface CAN to the instrument cluster (A1).