Actuate Supplemental Restraint System, Function - GF91.60-P-2012GW
Model 463 (except 463.342)
as of model year 2013 up to model year 2019
Model 463.342
Function requirements, general
- Circuit 15R ON
The electronic ignition lock control unit (N73) sends the status of circuit 15 over chassis CAN 1 (CAN E1) to the supplemental restraint system control unit (N2/10).
Actuate Supplemental Restraint System, general
The supplemental restraint system control unit continuously monitors the occupancy status of the front passenger seat and the status of the front seat belts (fastened or not fastened) and adapts its triggering behavior on the basis of this information.
The supplemental restraint system deployment function includes the following subfunctions:
- Function sequence system monitoring
- Function sequence for evaluation of occupation status on front passenger seat
- Function sequence for detecting the status of front seat belts
- Function sequence for impact detection
- Function sequence for frontal impact
- Function sequence in the event of a side impact
- Function sequence for rear impact Function sequence for rollover
- Function sequence for additional functions in event of crash
Function sequence system monitoring
When circuit 15R is switched on, the following indicator lamps are actuated:
- Supplemental restraint system indicator lamp (A1e15) in the instrument cluster (A1)
- Automatic child seat recognition airbag Off indicator lamp (N72/1e1) in the upper control panel control unit (N72/1)
After a successful self-test (t = 4 s), the supplemental restraint system indicator lamp is then switched off The corresponding occupancy status of the front passenger seat is shown via the automatic child seat recognition airbag off indicator lamp.
The request for switching on the supplemental restraint system indicator lamp is sent by the supplemental restraint system control unit via chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 (CAN E2) to the instrument cluster. The request to switch on the automatic child seat recognition airbag off indicator lamp is sent by the Supplemental Restraint System control unit via the chassis CAN 1, electronic ignition lock control unit, interior CAN (CAN B), SAM control unit (N10) and battery sensor LIN (LIN B15) to the upper control panel control unit, which directly actuates the automatic child seat recognition airbag off indicator lamp.
The supplemental restraint system control unit continues to monitor the supplemental restraint system while driving and signals faults to the driver via the multifunction display (A1p13) and the supplemental restraint system indicator lamp in the instrument cluster The request to display a corresponding message is sent by the supplemental restraint system control unit via chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The faults are stored in the nonvolatile memory of the supplemental restraint system control unit.
Model 463
as of model year 2015 up to model year 2019
with code ZU8 (National version for USA)
An accident data recorder is integrated in the Supplemental Restraint System control unit, which records relevant data before, during and after an accident. The data stored can be used to trace back the course of the accident.
Function sequence for evaluation of occupation status on front passenger seat
The deployment behavior of the restraint equipment at the passenger-side is matched to the occupancy status of the front passenger seat.
Function sequence for detecting status of front seat belts
The driver belt buckle restraint system switch (S68/3) or the front passenger belt buckle restraint system switch (S68/4) is actuated when the belt lock tongue is inserted into the belt buckle.
The Supplemental Restraint System control unit directly reads in the status of the restraint system switches.
The status of the rear seat belts does not have any influence on the deployment behavior of the restraint equipment.
Function sequence for impact detection
The Supplemental Restraint System control unit determines the acceleration forces acting on the vehicle using the following sensors:
- Integrated sensors
- Left frontal acceleration sensor (B48/1)
- Right frontal acceleration sensor (B48/2)
- Left B-pillar body acceleration sensor (B48/15) (model 463.23/27/34)
- Right B-pillar body acceleration sensor (B48/16) (model 463.23/27/34)
- Left front door pressure sensor (B48/17) (as of 01.09.2014 except code ZS8 (Protection class VR7/glass area VR9))
- Right front door pressure sensor (B48/18) (as of 01.09.2014 except code ZS8 (Protection class VR7/glass area VR9))
The sensor signals are read in directly by the supplemental restraint system control unit.
By evaluating the sensor signals, the Supplemental Restraint System control unit can distinguish between the following types of accident:
- Frontal impact
- Side impact
- Rear impact
- Rollover (along vehicle's longitudinal axis)
Function sequence for frontal impact
The deployment of the restraint equipment takes place depending on the severity of the impact, the occupancy of the front passenger seat and the status of the front seat belts. The occupation of the front passenger seat is detected by the signal of the seat occupied recognition for the front passenger seat and the ACSR (B48). The signal is received by the Supplemental Restraint System control unit over the seat occupancy LIN (LIN E2).
The following squibs can be ignited (maximum):
- Driver emergency tensioning retractor squib (R12/1)
- Front passenger emergency tensioning retractor squib (R12/2)
- Front passenger airbag squib 1 (R12/4)
- Left 2nd seat row emergency tensioning retractor squib (R12/6)
- Right 2nd seat row emergency tensioning retractor squib (R12/7)
- Driver airbag squib 1 (R12/13)
- Driver airbag squib 2 (R12/14)
The squibs are actuated directly by the supplemental restraint system control unit.
The following situations are taken into account:
- Occupancy status of the front passenger seat:
The supplemental restraint system control unit uses the current occupancy to decide about suppression or deployment of the front passenger airbag.
- Driver seat belt buckle status:
If the seat belt is not fastened, the driver airbag is triggered with advanced ignition timing instead of the driver emergency tensioning retractor.
- Front passenger seat belt buckle status:
If the seat belt is not fastened, the front passenger airbag is triggered with advanced ignition timing instead of the front passenger emergency tensioning retractor. However, this only applies if an occupied front passenger seat has been detected. Neither the emergency tensioning retractor nor the front passenger airbag is deployed if the seat is unoccupied.
Function sequence in the event of a side impact
The deployment of the restraint equipment takes place depending on the severity of the impact, the occupancy of the front passenger seat and the status of the front seat belts. The following squibs can be ignited (maximum):
- Driver ETR [GUS] squib
- Front passenger ETR [GUS] squib
- Left 2nd row ETR [GUS] squib
- Right 2nd row ETR [GUS] squib
- Driver side airbag squib (R12/9) (as of 01.09.2014, except model 463.342)
- Front passenger side airbag squib (R12/10) (as of 01.09.2014, except model 463.342)
- Left windowbag squib (R12/22) (model 463.23/27/34 except model 463.342)
- Right windowbag squib (R12/23) (model 463.23/27/34 except model 463.342)
- Driver pelvis airbag squib (R12/41) (as of 01.09.2014, except model 463.342)
- Front passenger pelvis airbag squib (R12/42) (as of 01.09.2014, except model 463.342)
The squibs are actuated directly by the supplemental restraint system control unit.
The following situations are taken into account:
- Occupancy status of the front passenger seat:
The supplemental restraint system control unit uses the current occupancy status of the front passenger seat to decide whether the passenger side sidebag and pelvis airbag are triggered.
- Driver/front passenger seat belt buckle status:
If the seat belt is not fastened, the relevant emergency tensioning retractor is not triggered.
Function sequence for rear impact
The deployment of the restraint equipment takes place depending on the severity of the impact and the status of the front seat belts. The following squibs can be ignited (maximum):
- Driver ETR [GUS] squib
- Front passenger ETR [GUS] squib
- Left 2nd row ETR [GUS] squib
- Right 2nd row ETR [GUS] squib
The squibs are actuated directly by the supplemental restraint system control unit.
If the seat belt is not fastened, the relevant emergency tensioning retractor is not triggered.
The following components can be actuated additionally:
- Driver NECK-PRO head restraint solenoid (Y24/12)
- Front passenger NECK-PRO head restraint solenoid (Y24/13)
After the NECK-PRO head restraints have been triggered, they can be reset again.
Function sequence for rollover
The deployment of restraint equipment takes place depending on the status of the front seat belts.
The following squibs can be ignited (maximum):
- Driver ETR [GUS] squib
- Front passenger ETR [GUS] squib
- Left rear emergency tensioning retractor squib
- Right rear emergency tensioning retractor squib
- Left windowbag squib (model 463.23/27/34 except model 463.342)
- Right windowbag squib (model 463.23/27/34 except model 463.342)
The squibs are actuated directly by the supplemental restraint system control unit.
If the seat belt is not fastened, the relevant emergency tensioning retractor is not triggered.
Function sequence for additional functions in event of crash
The additional functions in a crash event include the following subfunctions:
- Function sequence for activating the hazard warning flasher function
- Function sequence for switching on interior illumination
- 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 triggering the inerting system (with code Y65 (Alternative refrigerant) and gasoline engine)
- Function sequence for triggering the pyrofuse
- Function sequence for switching off the A/C
- Function sequence for shutting off the stationary heater (with code H12 (Stationary heater))
- Function sequence for automatic emergency call
- Function sequence for activating crash-active exit aid
Function sequence for activating the hazard warning flasher function
The hazard warning flasher function is activated automatically in order to warn other road users in the event of an accident. The supplemental restraint system control unit sends the crash signal over chassis CAN 1, electronic ignition lock control unit and interior CAN to the SAM control unit. The SAM control unit then activates the hazard warning flasher function.
The crash signal is also sent over a direct line from the supplemental restraint system control unit to the SAM control unit. The SAM control unit then generates a redundant crash signal on the interior CAN.
Function sequence for switching on interior illumination
In order to make it easier for the vehicle occupants or persons giving assistance to orientate themselves inside the vehicle in the event of an accident, the interior illumination is automatically activated. The supplemental restraint system control unit sends the crash signal over chassis CAN 1, electronic ignition lock control unit and interior CAN to the SAM control unit. The SAM control unit then activates the interior illumination.
The crash signal is also sent over a direct line from the supplemental restraint system control unit to the SAM control unit. The SAM control unit then generates a redundant crash signal on the interior CAN.
Function sequence for opening the central locking system
In order to make it possible for persons rendering assistance to gain access to vehicle occupants who may be injured in the event of an accident, the central locking is automatically unlocked. The supplemental restraint system control unit transmits the crash signal via chassis CAN 1, electronic ignition lock control unit and interior CAN to the following control units:
- Rear control unit (N10/8)
- Left front door control unit (N69/1)
- Right front door control unit (N69/2)
- Left rear door control unit (N69/3) (model 463.23/24/27/34)
- Right rear door control unit (N69/4) (model 463.23/24/27/34)
The central locking is unlocked after a waiting time of t = 8 to 11 s. In the event of a rear end collision, the central locking is immediately unlocked.
The crash signal is also sent over a direct line from the supplemental restraint system control unit to the SAM control unit. The SAM control unit then generates a redundant crash signal on the interior CAN.
Function sequence for opening the side windows
Smoke particles are produced in the vehicle interior when the pyrotechnical restraint equipment is triggered. The side windows at the front are opened automatically leaving a gap in order to allow these smoke particles to quickly disperse. The supplemental restraint system control unit transmits the crash signal via chassis CAN 1, electronic ignition lock control unit and interior CAN to the following control units:
- Left front door control unit
- Right front door control unit
The front door control units implement this request and the side windows are opened.
Function sequence for shutting off the engine
After an accident, the engine is automatically turned off to reduce the risk of fire. The Supplemental Restraint System control unit sends the crash signal via the chassis CAN 1 to the CDI control unit (N3/9) (engine 642) or to the ME-SFI [ME] control unit (N3/10) (engine 157, 273). On vehicles with engine 176, the Supplemental Restraint System control unit sends the crash signal via the chassis CAN 1, powertrain control unit (N127) and engine CAN (CAN C1) to the ME-SFI [ME] control unit. The CDI control unit or the ME-SFI [ME] control unit then triggers the switching off of the engine.
The crash signal is also transmitted via a direct line by the supplemental restraint system control unit to the CDI control unit or to the ME-SFI [ME] control unit.
Function sequence for triggering the inerting system (with code Y65 (Alternative refrigerant) and gasoline engine)
The inerting system prevents any leaking refrigerant from the A/C system igniting on hot parts of the engine.
If the supplemental restraint system control unit detects a frontal impact, it actuates the inerting system squib (R12/70). If the inerting system squib is deployed, Argon inert gas flows out of the gas cylinder into the engine compartment. This displaces the atmospheric oxygen in areas close to the engine that present a fire hazard. This prevents the risk of fire caused by refrigerant flowing out of the air conditioning system.
Function sequence for triggering the pyrofuse
In order to avoid a possible risk of fire following an accident, the pyrofuse (F32/3f150) in the engine compartment prefuse box (F32/3) is triggered.
Inside the housing, the main line is designed as bus bar with predetermined fracture point (3). After a corresponding crash event has occurred, the pyrofuse is directly actuated by the supplemental restraint system control unit. Because of the actuation, pressure builds up in the chamber (1). The piston (2) then moves against the predetermined fracture point, thereby disconnecting the bus bar.
Time sequence: T
Piston movement starts after t = 300 μs.
The bus bar disconnection is terminated after t = 450 μs.
By triggering the pyrofuse, the starter (M1) and the alternator (G2) are disconnected from the on-board electrical system.
Function sequence for switching off the A/C
In order to prevent hazardous gases from entering the vehicle interior after an accident, the climate control control and operating unit (N22/7) shuts off the air conditioning and closes the air recirculation flap. The Supplemental Restraint System control unit sends the crash signal via the chassis CAN 1, electronic ignition lock control unit and interior CAN to the climate control control and operating unit, which implements this request.
Function sequence for shutting off the stationary heater (with code H12 (Stationary heater))
After an accident, the stationary heater is automatically turned off to reduce the risk of fire. The supplemental restraint system control unit transmits the crash signal via chassis CAN 1, the electronic ignition lock control unit and the interior CAN to the stationary heater control unit (A6n1), which prompts a shutoff of the stationary heater.
Function sequence for automatic emergency call
An emergency call is made automatically after an accident.
Depending on the type of transmission involved the following data, among others, are sent to the Mercedes-Benz Emergency Call Center:
- Vehicle GPS positioning data (global navigation system)
- Last known GPS position data for vehicle route
- Direction of travel
- Vehicle identification number
- Type of drive in vehicle
Function sequence for activating crash-active exit aid
To make it easier for the driver to exit the vehicle or for first aiders to remove the driver from the vehicle after an accident, following a crash event, the steering column is automatically adjusted upward to a predefined position if the following occurs:
- Driver door opened
- Change of circuit 15C ON status to circuit 15C OFF
The supplemental restraint system control unit transmits the crash signal via chassis CAN 1, electronic ignition lock control unit and interior CAN to the driver seat control unit (N32/1), which controls the crash-active easy exit function.
| Electric function schematic for deployment of supplemental restraint system | PE91.60-P-2055-97ZGA | ||
| Overview of system components for supplemental restraint system | GF91.60-P-9996GW |