GF91.60-P-2001GM Deploy Supplemental Restraint System, Function
GF91.60-P-2001GM Deploy Supplemental Restraint System, Function
General function requirements
^ Circuit 5R On
Deploying supplemental restraint system, general
The supplemental restraint system (SRS) constantly monitors the occupied status of the front passenger seat (with code (U18) Automatic child seat recognition (ACSR [AKSE]) or with code (494) USA version) as well as the status of the front seat belts (fastened or not fastened) and adapts its deployment response based on this information.
The trigger SRS function consists of the following subfunctions:
^ Function sequence for detecting occupied status of front passenger seat
^ Function sequence for detecting status of front seat belts
^ Impact detection function sequence
^ Function sequence for monitoring frontal impact
^ Function sequence for monitoring side impact
^ Function sequence for monitoring rear end collision
^ Function sequence for monitoring roll-over process
Function sequence for detecting occupied status of front passenger seat
The restraint systems control unit (N2/7) receives the corresponding information from the following components:
- Front passenger seat occupied recognition and automatic child seat recognition (B48) (with code (U18) Automatic child seat recognition (ACSR [AKSE]))
- WSS (Weight Sensing System) control unit (N2/13) (with code (494) USA version)
Function sequence for detecting status of front seat belts
The driver seat belt buckle and seat belt reminder warning switch (S68/1) or the front passenger seat belt buckle and seat belt reminder warning switch (S68/2) is actuated by the belt latch which is inserted into the seat belt buckle. This is read in directly by the restraint systems control unit.
For model 164 (without code (494) USA version and without code (498) Japan version) the seat belt buckles for the 2nd seat row are also equipped with a seat belt buckle query. However, this is only used for the status indication in the instrument cluster (A1) and does not affect the triggering characteristic of the SRS in any way.
This means that in the event of a crash the emergency tensioning retractors for the 2nd and 3rd seat row are also deployed even if the belt latches are not inserted.
Impact detection function sequence
The restraint systems control unit determines the acceleration acting on the vehicle with the aid of its integrated sensor and the following sensors:
- Drive sidebag sensor (A53)
- Front passenger sidebag sensor (A54)
- Driver-side frontal acceleration sensor (B48/1)
- Passenger-side frontal acceleration sensor (B48/2)
- Driver door pressure sensor (B48/7)
- Front passenger door pressure sensor (B48/8)
- Rear door pressure sensor, driver-side (B48/9) (with code (293) Left and right rear sidebag)
- Rear door pressure sensor, passenger-side (B48/10) (with code (293) Left and right rear sidebag)
With the aid of this sensor system, the SRS is able to distinguish between the following types of impacts:
- Head-on collision
- Side-on collision
- Rear end collision
Function sequence for monitoring frontal impact
A frontal impact is detected by the restraint systems control unit via the signals from the following components:
- Integrated sensor in the restraint systems control unit
- Driver-side frontal acceleration sensor
- Passenger-side frontal acceleration sensor
The restraint equipment is deployed depending on the severity of the impact, the occupation of the front passenger seat, and the status of the front seat belts.
The following maximum number of squibs can be ignited:
- Passenger airbag squib 1 (R12/4)
- Passenger airbag squib 2 (R12/5)
- Left 2nd row emergency tensioning retractor squib (R12/6)
- Right 2nd row emergency tensioning retractor squib (R12/7)
- Driver airbag squib 1 (R12/13)
- Driver airbag squib 2 (R12/14)
- Driver kneebag squib (R12/25) (with code (294) Kneebag)
- Pyrotechnical separator (K88) (for model 164.8 with engine 642)
- Left 3rd seat row emergency tensioning retractor squib (R12/35) (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
- Right 3rd seat row emergency tensioning retractor squib (R12/36) (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
- Drive buckle ETR squib (R46)
- Front passenger ETR squib (46/1)
The following situations are taken into account:
- Occupied state of the front passenger seat:
The restraint systems control unit uses the current occupancy to decide whether to suppress the front passenger airbag unit or to use 1-stage or 2-stage deployment.
- Status of driver seat belt buckle and seat belt reminder warning:
If the driver seat belt buckle and seat belt reminder warning switch detects that a belt latch is not inserted into the seat belt buckle, then the driver airbag unit with advanced ignition timing is triggered instead of the driver emergency tensioning retractor unit.
- Status of front passenger seat belt buckle and seat belt reminder warning:
If the front passenger seat belt buckle and seat belt reminder warning switch detects that a belt latch is not inserted into the seat belt buckle, then the front passenger airbag unit with advanced ignition timing is triggered instead of the front passenger emergency tensioning retractor unit.
This only applies, however, if the front passenger seat is known to be occupied. If not occupied then neither the emergency tensioning retractor nor the front passenger airbag unit are triggered.
Function sequence for monitoring side impact
A side impact is detected by the restraint systems control unit via the signals from the following components:
- Integrated sensor in the restraint systems control unit
- Driver sidebag sensor
- Front passenger sidebag sensor
- Driver door pressure sensor
- Front passenger door pressure sensor
- Rear door pressure sensor, driver-side (with code (293) Left and right rear sidebag)
- Rear door pressure sensor, passenger-side (with code (293) Left and right rear sidebag)
The restraint equipment is deployed depending on the severity of the impact, the occupation of the front passenger seat, and the status of the front seat belts.
The following maximum number of squibs can be ignited:
- Driver buckle ETR squib
- Front passenger buckle ETR squib
- Left 2nd row ETR [GUS] squib
- Right 2nd row ETR [GUS] squib
- Left 3rd seat row emergency tensioning retractor squib (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
- Right 3rd seat row emergency tensioning retractor squib (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
- Driver sidebag squib (R12/9)
- Front passenger sidebag squib (R12/10)
- Left sidebag squib for 2nd seat row (R12/11) (with code (293) Left and right rear sidebag)
- Right sidebag squib for 2nd seat row (R12/12) (with code (293) Left and right rear sidebag)
- Left windowbag squib (R12/16)
- Right windowbag squib (R12/17)
The following state is taken into consideration:
- The restraint systems control unit makes its decision regarding triggering the front passenger sidebag unit based on the current occupancy of the front passenger seat.
Function sequence for monitoring rear end collision
A rear end collision is detected by the restraint systems control unit via the signals from the following components:
- Integrated sensor in the restraint systems control unit
- Driver sidebag sensor
- Front passenger sidebag sensor
- Driver-side frontal acceleration sensor
- Passenger-side frontal acceleration sensor
The activation 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 (at most):
- Driver buckle ETR squib
- Front passenger buckle ETR squib
- Left 2nd row ETR [GUS] squib
- Right 2nd row ETR [GUS] squib
- Left 3rd seat row emergency tensioning retractor squib (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
- Right 3rd seat row emergency tensioning retractor squib (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
Actuation also takes place over the:
- Driver NECK-PRO head restraint solenoid (Y24/12)
- Front passenger NECK-PRO head restraint solenoid (Y24/13)
The following situations are taken into account:
- Driver seat belt buckle and seat belt reminder warning switch status:
If the driver seat belt buckle and seat belt reminder warning switch detects that a belt latch is not inserted into the seat belt buckle, the driver emergency tensioning retractor unit is not activated.
- Front passenger seat belt buckle and seat belt reminder warning switch status:
If the front passenger seat belt buckle and seat belt reminder warning switch detects that a belt latch is not inserted into the seat belt buckle, the front passenger emergency tensioning retractor unit is not activated.
Function sequence for monitoring roll-over process
A rollover is detected by the restraint systems control unit via the integrated sensor.
The following maximum number of squibs can be ignited:
- Driver buckle ETR squib
- Front passenger buckle ETR squib
- Left 2nd row ETR [GUS] squib
- Right 2nd row ETR [GUS] squib
- Left 3rd seat row emergency tensioning retractor squib (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
- Right 3rd seat row emergency tensioning retractor squib (for model 251 and for model 164.8 with code (845) 3rd seat row folding down electrically)
The following situations are taken into account:
- Driver seat belt buckle and seat belt reminder warning switch status:
If the driver seat belt buckle and seat belt reminder warning switch detects that a belt latch is not inserted into the seat belt buckle, the driver emergency tensioning retractor unit is not activated.
- Front passenger seat belt buckle and seat belt reminder warning switch status:
If the front passenger seat belt buckle and seat belt reminder warning switch detects that a belt latch is not inserted into the seat belt buckle, the front passenger emergency tensioning retractor unit is not activated.
