Foresighted occupant protection, function - GF91.60-P-2010B

MODEL 215, 220 as of 1.9.02

The PRE-SAFE (foresighted occupant protection) safety system comprises a package with the functions:

Reversible electrical retractor tensioner (RevAS)
Conditioning of the seats
Automatic closure of the tilting/sliding roof

The systems are activated in a critical driving condition, in other words in a potential accident situation.

By the belt tensioning taking place before the actual impact, the adjustment of the front passenger's seat (with individual rear seats also the rear seats) to an upright position and closure of the tilting/sliding roof (SHD) (M12) for a subsequent crash an optimum prerequisite should be created for an expected accident.

Conditions of operation

Circuit 15C ON

The control modules for foresighted occupant protection are located in the left front reversible emergency tensioning retractor (A76) and right front reversible emergency tensioning retractor (A76/1) which are fitted in the B-pillars.

Function

If brake assistant (BAS) is active during a brake application (longitudinal dynamics), the BAS sends a CAN message. This signal is checked for plausibility via the stop lamp. If an emergency braking situation is recognized the reversible retractor tensioner and the seats are activated.

If a skid situation is recognized (lateral dynamics) the seats and the tilting/sliding roof are activated.

Triggering

The system is triggered under the following critical conditions:

Emergency stop
Oversteer
Understeer

The PRE-SAFE triggering threshold is increased for lateral acceleration, if electronic stability program/acceleration slip regulation (ESP/ASR) is switched off manually.

Triggering process

Triggering only takes place when the buckle is inserted.

Seats:

The seat backrest is adjusted for a backrest angle >16° from the front stop
The front passenger-side height adjustment is adjusted fully upwards
Seat adjustment by approx. 80 to 100 mm rearwards, provided the seat is located too far in the forward position

The front passenger's head restraint is not adjusted.

Seat belt:

Seat belt slack on the driver's and front passenger's side is eliminated (tensioning force approx.140 N)
Tensioning duration 10 seconds
Tensioning travel up to 80 mm

Tilting/sliding roof (SHD) (M12)

In a skid situation (lateral dynamics) the tilting/sliding roof (SHD) (M12) is actuated and closed.

If the system recognizes a critical situation, the seat belts are preloaded noticeably so that the driver and front passenger have better restraint protection.

Fault message

Faults are stored and the message PRE-SAFE INACTIVE - locate workshop is displayed in the instrument cluster.

Block diagram for PRE-SAFE system with the equipment, individual rear seats, electrically adjustable, with heated seats and memory package (code 224c)

Fig 1: PRE-SAFE System - Block Diagram

Data exchange

The tilting/sliding roof (SHD) (M12) and right front seat adjustment motor group with memory (M28) and right rear seat adjustment motor group (18/2) and left rear seat adjustment motor group (18/1) are actuated via the engine compartment CAN to the central gateway control module (N93).

The signals included are converted into an interior CAN message in the central gateway control module (N93). The left PRE-SAFE control module controls the left front reversible emergency tensioning retractor (A76) and the tilting/sliding roof (SHD) (M12). The right PRESAFE control module controls the right front reversible emergency tensioning retractor (A76/1), the right front seat adjustment control module with memory (N32/2) and the tilting/sliding roof (SHD) (M12).

Functions which can be called up via the Diagnosis Assistant System (DAS)

Via the request from the PRE-SAFE control module:

The seat is moved into the PRE-SAFE position
Approaching the PRE-SAFE position is stopped
Message in the instrument cluster actuated on a test basis
The sliding roof is closed

All PRE-SAFE functions can be switched off for the seats.

Seat belt tensioner control module with airbag, location/task/design/function

GF91.60-P-4006B