Restraint systems control unit, component description - GF91.60-P-4048GZ

MODEL 164 

Location 

The restraint systems control unit is located on the center tunnel between the front seats.

Task 

The restraint systems control unit is used to ensure passive occupant protection. The restraint systems control unit deploys the restraint systems in the event of an accident. These include, e.g. the airbag units and emergency tensioning retractors. The restraint systems control unit has self-monitoring and fault monitoring features. Head-on, rear-end, and side impact collisions are recorded, and a distinction is made between the different types of collision.

Roll-overs around the longitudinal vehicle axis can also be detected.

For code (494) USA version:

In the event of an accident, an automatic emergency call is also sent over the emergency call system control unit (N123/4).

Scope of task 

• Crash recognition and ignition point recognition
• To trigger ignition stages in event of collision, taking crash evaluation during a collision into consideration
• Evaluation of front passenger seat occupied and child seat recognition sensor (B48) (not with code (494) USA version)
• Evaluation of Weight Sensing System (WSS) (with code (494) USA version)
• Actuation of digital crash output, separately and via Controller Area Network Bus Class C (engine compartment) (CAN-C) (with code (494) USA version)
• Output of redundant crash signal over discrete lines to ME control unit (N3/10) and rear SAM control unit (N10/8) (as of 1.6.07)
• Power supply and evaluation of following sensors:
  • Driver sidebag sensor (A53)
  • Front passenger sidebag sensor (A54)
  • Driver 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)

  With code (293) Left and right rear sidebag:

  • Rear door pressure sensor, passenger side (B48/10)
  • Rear door pressure sensor, driver-side (B48/9)
• To be a power backup in a "self-sufficiency instance", in the event of a battery failure after a collision
• Self-testing and permanent monitoring of system and fault display with nonvolatile storage of faults and failure time
• Storage of nonvolatile crash telegrams
• Programming capability in terms of equipment and crash parameters
• Fault output via interface after initiating diagnosis communication
• System readiness display over CAN-C to the instrument cluster (A1)
• Evaluation of integrated rollover sensor
• Support of automatic seat belt reminder warning over CAN-C
• Sleep function

Seat belt warning lamp function (A1e9) 

The seat belt warning lamp is located in the instrument cluster.

After starting the engine, the seat belt warning lamp lights up for a maximum of 6 seconds and a buzzer sounds in order to remind the driver or front passenger (if available) to buckle up.

If the driver or front passenger is not belted after these 6 seconds and a speed of 25 km/h (15 mph) has not been exceeded, the seat belt warning lamp lights up until the driver and front passenger are belted.

If a speed of 25 km/h (15 mph) has been exceeded (driver or front passenger not belted), the seat belt warning lamp starts to flash on and off for a maximum of 60 s after the speed has been exceeded and a warning sound is emitted.

If the driver or front passenger is still not belted after these 60 seconds, the warning sound goes off and the seat belt warning lamp stops flashing on and off. The seat belt warning lamp stays on until the driver and front passenger are belted.

The seat belt warning lamp will only go out, if the driver and the front passenger are belted or the vehicle is standing and one front door is open.

Objects on the front passenger seat can be identified as person due to their weight and lead to a warning.

Indicator and warning lamp airbag function (A1e15) 

The airbag indicator and warning lamp is located in the instrument cluster. If the airbag indicator and warning lamp lights up during the journey the supplemental restraint system is faulty. In such a case the restraint equipment may be unintentionally deployed or not at all in the event of an accident.

Automatic child seat recognition airbag OFF indicator lamp function (N72/1e1) 

The Airbag OFF indicator lamp is located in the upper control panel control unit.

The airbag OFF indicator lamp indicates the functional availability of the automatic child seat recognition system and that the front passenger airbag has been turned off if a special child seat is detected.

Self-test, function 

When c. 15R is activated, the restraint systems control unit performs a self-test for restraint system.

In the process, the airbag indicator and warning lamp in the instrument cluster and the airbag OFF indicator lamp in the upper control panel control unit are actuated for 4 seconds via the central gateway control unit (N93). If the self-test was successful, both indicator lamps are switched off.

If the self-test was not successful, the airbag indicator and warning lamp remains switched off. However, the restraint systems control e. unit remains ready for triggering.

If the airbag OFF indicator lamp and the airbag indicator and warning lamp light up at the same time, there is a malfunction in the weight sensing system and the front passenger airbag is deactivated (only with code (494) USA version).

Discrete inputs 

• Circuit 15R
• Circuit 31
• Circuit 30
• Driver sidebag sensor
• Front passenger sidebag sensor
• Front passenger seat occupied and child seat recognition sensor
• Driver-side frontal acceleration sensor
• Passenger-side frontal acceleration sensor
• Driver door pressure sensor
• Front passenger door pressure sensor
• Rear door pressure sensor, driver-side
• Rear door pressure sensor, passenger-side
• Driver seat belt buckle and seat belt warning switch (S68/1)
• Front passenger seat belt buckle and seat belt warning switch (S68/2)
• Left rear belt buckle switch (S68/11) (up to 31.5.06)
• Right rear belt buckle switch (S68/12) (up to 31.5.06)
• Center rear seat belt buckle switch (S68/14) (up to 31.5.06)
• Left seat belt buckle switch on 3rd seat row (S68/16) (model 164.8 up to 31.5.06)
• Right seat belt buckle switch on 3rd seat row (S68/17) (model 164.8 up to 31.5.06)

Discrete outputs 

• Driver airbag squib 1 (R12/13)
• Driver airbag squib 2 (R12/14)
• Passenger airbag squib 1 (R12/4)
• Passenger airbag squib 2 (R12/5)
• Driver sidebag squib (R12/9)
• Front passenger sidebag squib (R12/10)
• Left windowbag squib (R12/16)
• Right windowbag squib (R12/17)
• 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 3rd seat row emergency tensioning retractor squib (R12/35) (model 164.8)
• Right 3rd seat row emergency tensioning retractor squib (R12/36) (model 164.8)
• Left 2nd row emergency tensioning retractor squib (R12/6)
• Right 2nd row emergency tensioning retractor squib (R12/7)
• Drive buckle ETR squib (R46)
• Front passenger ETR squib (R46/1)
• Solenoid for NECK-PRO head restraint, driver (Y24/12) (with code (494) USA version or with code (438) NECK-PRO)
• Solenoid for NECK-PRO head restraint, front passenger (Y24/13)

  (with code (494) USA version or with code (438) NECK-PRO)

• Digital crash output via emergency call system control unit (with code (494) USA version)
• ME control unit (redundant crash signal as of 1.6.07)
• Rear SAM control unit (redundant crash signal as of 1.6.07)

  The restraint system control unit has integrated sensors. For this reason, do not remove the restraint equipment control unit when the power supply is activated, as otherwise airbags and emergency tensioning retractors trigger. All work performed on or with the restraint systems control unit may only be conducted when the battery (G1) has been disconnected and after a waiting time of approx. ≥ 60 s.