GF91.60-P-0002GM Supplemental Restraint System (SRS), Function

GF91.60-P-0002GM Supplemental Restraint System (SRS), Function

Function requirements, general
^ The supplemental restraint system (SRS) must be programmed to the vehicle (left or right-hand drive vehicle, equipment programming and configuration parameters)
^ C. 15R On

Supplemental restraint system, general
The supplemental restraint system is used for occupant protection.

The SRS comprises the following subfunctions:
^ System monitoring function sequence
^ Power reserve function sequence
^ Belt lock system function sequence
^ Function sequence of additional functions in the event of a crash

Further partial functions are described in separate documents:
^ Passenger-side seat occupied recognition, function (with code (U18) Automatic child seat recognition (ACSR [AKSE]))
^ Passenger-side seat occupied recognition, function (with code (494) USA version)
^ Deploy supplemental restraint system, function
^ Deploying of pyrofuse, function (for model 164.8 with engine 642)

System monitoring function sequence
The supplemental restraint system continuously monitors itself and signals faults to the driver via the airbag indicator and warning lamp (A1e15) in the instrument cluster (A1). In addition, the automatic child seat recognition airbag OFF indicator lamp (N72/1e1) (with code (U18) Automatic child seat recognition (ACSR [AKSE]) or with code (494) USA version) in the upper control panel control unit (N72/1) is switched on. All faults are stored in the nonvolatile memory of the restraint systems control unit (N2/7). The indicator lamps are switched off after t = 4 sec following a successful self-test.

Power reserve function sequence
The restraint systems control unit provides power reserves for at least t = 300 ms if the battery has been disconnected.

Belt lock system function sequence
Irrespective of the restraint systems control unit, the belt is prevented from extending in certain situations.

Function sequence of additional functions in the event of a crash
The additional functions in the event of a crash comprise the following subfunctions:
^ Function sequence for activation of hazard warning function
^ Function sequence for opening the central locking system
^ Function sequence for opening the side windows
^ Function sequence for shutting off the engine
^ Function sequence for shutting off the stationary heater (STH) (with code (228) Stationary heater)
^ Function sequence for automatic emergency call (with code (494) USA version with code (359) TELE AID emergency call system)
^ Function sequence for activation of crash-active exit aid (as of 1.7.09 with code (275) Memory package (driver seat, steering column, mirrors))

Additional function requirements for activation of hazard warning function
^ Deceleration a > 4 g

Function sequence for activation of hazard warning function
The hazard warning function is activated automatically after a crash event has occurred. The crash signal is transmitted by the restraint systems control unit over the engine compartment CAN (CAN C) to the central gateway control unit (N93) and then routed by it to the interior CAN (CAN-B).
The rear SAM control unit (N10/8) receives the signal and actuates the following lamps directly:
- Left turn signal light (E3e1) (without code (849) Spare tire holder/spare tire)
- Right turn signal lights (E4e1) (without code (849) Spare tire holder/spare tire)
- Left turn signal lights (E3/5e1) (with code (849) Spare tire holder/spare tire)
- Right turn signal lights (E4/5e1) (with code (849) Spare tire holder/spare tire)

The rear SAM control unit transmits the crash signal via interior CAN. The following lamps are then actuated:
- the front SAM control unit (N10) actuates the left turn signal lights (E1e5) and right turn signal lights (E2e5)
- the left front door control unit (N69/1) actuates the left outside mirror turn signal lamp (E6/5)
- from the right front door control unit (N69/2) the right outside mirror turn signal lamp (E6/6)

The hazard warning function can be deactivated by pressing the hazard warning system switch (N72/1s5) in the upper control panel control unit.

The restraint systems control unit also transmits a redundant crash signal to the rear SAM control unit via a direct line.

Additional function requirements for opening the central locking system
^ Deceleration a > 6 g

Function sequence for opening the central locking system
The central locking is unlocked automatically after a crash event has occurred. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the central gateway control unit and routed by it to the interior CAN. The following motors are then actuated:
- Left front door central locking motor (M14/6) by the left front door control unit
- Right front door central locking motor (M14/5) by the right front door control unit
- Left rear door central locking motor (M14/8) by the front SAM control unit
- Right rear door central locking motor (M14/9), rear-end door locking unit (A72) and spare tire carrier central locking motor (M14/13) by the rear SAM control unit (with code (849) Spare tire holder/spare tire)

The central locking is unlocked after a waiting time of t = 8 s to t = 11 s.

The restraint systems control unit also transmits a redundant crash signal to the rear SAM control unit via a direct line.

Function sequence for opening the side windows
After a crash event occurs, the side windows are automatically opened. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the central gateway control unit and routed by it to the interior CAN. The following power window motors are then actuated as follows:
- Left front power window motor (M10/3) by the left front door control unit
- Right front power window motor (M10/4) by the right front door control unit
- Left rear power window motor (M10/5) and right rear power window motor (M10/6) by the front SAM control unit

The tilting/sliding roof (with code (414) Power glass tilting/sliding roof) or the panoramic sliding sunroof (model 251 with code (413) Panoramic glass sunroof with top sliding sunroof) is opened. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the central gateway control unit and routed by it to the interior CAN.

The overhead control panel control unit (N70) receives the signal and actuates with code (414) Power glass tilting/sliding roof the tilting/sliding roof (SR [SHD]) drive unit (M12) towards open. On model 251 with code (413) Panoramic glass sunroof with top sliding sunroof, the overhead control panel control unit actuates the roller sun blind drive unit (M12/5), the drive unit 1, panoramic sliding sunroof (M12/6) and the drive unit 2, panoramic sliding sunroof (M12/7) towards open.

Function sequence for shutting off the engine
The engine is shut off automatically after a crash event has occurred. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the CDI control unit (N3/9) (for diesel engine) or to the ME-SFI [ME] control unit (N3/10) (for gasoline engine). This then causes the engine to be shut off.

Function sequence, STH shutoff (with code (228) Stationary heater)
The STH is shut off automatically after a crash event has occurred. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the central gateway control unit and routed by it to the interior CAN. The STH control unit (A6n1) receives the signal and shuts off the STH.

Function sequence for automatic emergency call (with code (494) USA version with code (359) TELE AID emergency call system)
An emergency call is made automatically after a crash event has occurred. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the central gateway control unit and routed by it to the diagnosis CAN. The emergency call system control unit (N123/4) receives the signal and automatically makes an emergency call.

The crash signal is also transmitted via a direct line from the restraint systems control unit to the emergency call system control unit.

Function sequence for activating crash-active exit aid (as of 1.7.09 with code (275) Memory package (driver seat, steering column, mirrors))
Following the occurrence of a crash event the driver seat and the steering column are automatically moved to a defined position. The crash signal is transmitted by the restraint systems control unit via the engine compartment CAN to the central gateway control unit and routed by it to the interior CAN. The following motors are actuated by the driver-side front seat adjustment control unit with memory (N32/1):
- Steering column up/down motor (M20/2)
- Driver seat longitudinal adjustment motor (M27/1)
- Driver rear seat height adjustment motor (M27/2)
- Driver front seat height adjustment motor (M27/3)
- Driver head restraint motor (M27/4)
- Driver backrest angle adjustment motor (M27/5)

The steering column is always moved upwards in the event of a crash event.