Component description for front reversible emergency tensioning retractors - GF91.40-P-4020FL

MODEL 212 

Shown on model 212.0 

Fig 1: Front Reversible Emergency Tensioning Retractors - Shown On Model 212.0

Courtesy of MERCEDES-BENZ USA

Location 

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

Task 

The reversible emergency tensioning retractors have the task of tensioning the seat belt in certain hazardous situations by actuating the integrated actuator motors, in order to hold the driver and the front passenger in their seat positions and thereby minimize the consequences of a possible accident. If the seat belt adjustment function is active, the seat belt slack is also reduced when the seat belt is fastened.

The tasks are subdivided as follows:

• Reading in of signals 
• Evaluation of input factors 
• Transmitting signals 
• Actuation of components 

Reading in of signals 

The input factors are read in via the following connection:

• Chassis CAN (CAN E) (up to 28.2.13) or chassis CAN 1 (CAN E1) (as of 1.3.13) 

Chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) 

The following signals are read in via the chassis CAN or chassis CAN 1:

• Sent from Supplemental Restraint System control unit (N2/10):
  • Status of driver seat belt buckle restraint system switch (S68/3)
  • Status of front passenger seat belt buckle restraint system switch (S68/4)
  • Crash signal
• Transmitted by the Electronic Stability Program control unit (N30/4) (model 212 (except 212.074/077/095/098/274/277/298) without code (233) DISTRONIC PLUS) or the regenerative braking system control unit (N30/6) (model 212.095/098/298) or the Premium Electronic Stability Program control unit (N30/7) (model 212 (except 212.095/098/298) with code (233) DISTRONIC PLUS, model 212.074/077/274/277):
  • PRE-SAFE status
  • PRE-SAFE stage
• Transmitted by the instrument cluster (A1):
  • Status of seat belt adjustment function

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Evaluation of input factors 

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

Transmitting signals 

The reversible emergency tensioning retractors send signals over the following connection:

• Chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) 

Chassis CAN (up to 28.2.13) or chassis CAN 1 (as of 1.3.13) 

The following signal is transmitted via the chassis CAN or chassis CAN 1:

• Request to instrument cluster to display fault message

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Actuation of components 

Components are actuated with the following connection:

• Direct internal line 

Direct internal line 

The following components are actuated via direct internal lines:

• Left front reversible emergency tensioning retractor actuator motor
• Right front reversible emergency tensioning retractor actuator motor