Reversible emergency tensioning retractor, component description - GF91.60-P-4050GZ

MODEL 164

Fig 1: Identifying Left/Right Front Reversible Emergency Tensioning Retractor

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The left front reversible emergency tensioning retractor (A76) and right front reversible emergency tensioning retractor (A76/1) are located in the B-pillars. The reversible emergency tensioning retractors have their own integrated PRE-SAFE control unit.

General

The left and right front reversible emergency tensioning retractors are also known as "reversible electrical reel retractors". The reversible emergency tensioning retractors are the core of a PRESAFE system. An activation of the PRE-SAFE control unit occurs in a critical driving situation, i.e. in a potential accident situation.

The PRE-SAFE adjustment just prior to the actual impact should help to provide an improved situation for the occupants prior to a collision.

Fig 2: Identifying Left/Right Front Reversible Emergency Tensioning Retractor

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Control unit task scope:

Detection of a critical driving situation such as an emergency stop or a skidding situation
Triggering of the electrical reel retractor
Transmission of the emergency stop or skidding message to the Controller Area Network bus Class C (engine compartment) (CAN-C)
Actuation of the overhead control panel control unit (N70) to close the power sliding roof, only when equipped with glass electric power sliding roof (Code 414)

The necessary information is received by the PRE-SAFE control unit over the CAN-C.

Electric reel retractor, task scope:

Rolling up belt
(Electric) belt tensioning
Releasing belt

Variations

There are different mechanical variants, e.g. manual child safety lock in retractor on passenger-side in USA version.

There are different variant codings for left-hand and right-hand drive vehicles.