Seat Belt Tensioner: Description and Operation

GF91.40-P-4020FL Front Reversible Emergency Tensioning Retractor, Component Description

Component Identification:

Location
The reversible emergency tensioning retractors are located in the respective B-pillar.

Task
The reversible emergency tensioning retractors perform the following tasks:
^ Reading in of signals
^ Evaluation of input factors
^ Actuation of components

Reading in of signals
The input factors are read in via the following connection:
^ Chassis CAN (CAN E)

Chassis CAN
The following signals are read in over the chassis CAN:
- provided by the supplement restraint system control unit (N2/10):
- Status of driver seat belt buckle restraint system switch (S68/3) and front passenger seat belt buckle restraint system switch (S68/4)

- provided by the Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS) or Electronic Stability Program Premium control unit (N30/7) (with code (233) DISTRONIC PLUS):
- Request for reversible emergency tensioning retraction

- provided by the instrument cluster (A1):
- Request to perform seat belt slack reduction function

Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the affected components are then actuated.

Actuation of components
The actuation of the components takes place via the following connections:
^ Chassis CAN
^ Direct line

Chassis CAN
The following components are actuated via the chassis CAN:
- Instrument cluster

Direct line
The following components are actuated via a direct line:
- Left front reversible emergency tensioning retractor actuator motor
- Right front reversible emergency tensioning retractor actuator motor