Restraint systems control unit, task - GF91.60-P-4018-01QMC

The restraint systems control unit (N2/7) ensures the proper functioning of the passive interior compartment protection. The restraint systems control unit (N2/7) triggers restraint systems when an accident occurs. These systems include all the airbags as well as the emergency tensioning retractors and the buckle emergency tensioning retractors. The restraint systems control unit (N2/7) has self-monitoring and fault-monitoring functions. Head-on, rear-end and side impact collisions are recorded, and a distinction is made between the different types of collision. The restraint systems can be actuated using conventional squibs.

The restraint systems control unit performs the following tasks:

• Collision detection and ignition time determination
• Ignition stage triggering when collision occurs
• Provide voltage supply for the peripheral acceleration pickups, consisting of the driver-side frontal acceleration sensor (B48/1), passenger-side frontal acceleration sensor (B48/2), left sidebag and windowbag sensor (A53/1) and right sidebag and windowbag sensor (A54/1)
• Energy reserves for self-sufficiency case (if battery torn off when collision occurs)
• Communication over the Controller Area Network Bus Class B (interior) (CAN-B) with the WSS (Weight Sensing System) control unit (N2/13) to determine the status of the front passenger seat
• Actuation of digital crash output, individually and via CAN-B
• Storing of non-volatile collision telegrams
• Self-testing and permanent monitoring of system and fault display with non-volatile storage of faults and failure time
• Programming capability with respect to vehicle equipment and crash parameters via the CAN interface
• Assignment of means of ignition to the ignition circuits via the ignition means assignment table
• Functional doubling of ignition circuits via the function coupling table
• Output of faults via the CAN-B interface after initiation of diagnosis communication
• System readiness indicator status transmitted to instrument cluster via CAN-B (A1)

Any work on or with the restraint systems control unit (N2/7) while it is connected must only be done with the ignition key removed ("Circuit 15C OFF").

The restraint systems control unit (N2/7) has the following inputs:

• Terminal 15
• Circuit 15R
• (Circuit 31)
• Left sidebag and windowbag sensor (A53/1) and right sidebag and windowbag sensor (A54/1)
• Driver-side frontal acceleration sensor (B48/1) and passenger- side frontal acceleration sensor (B48/2)
• Driver seat belt buckle restraint systems switch (S68/3) and front passenger seat belt buckle restraint systems switch (S68/4)

The restraint systems control unit (N2/7) has the following 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)
• Front left sidebag squib (R12/20)
• Right front sidebag squib (R12/21)
• left rear sidebag squib (R12/11)
• right rear sidebag squib (R12/12)
• Driver ETR squib (R12/1)
• Front passenger ETR squib (R12/2)
• Left rear ETR squib (R12/6)
• Right rear ETR squib (R12/7)
• Digital crash output to the emergency call system control unit (N123/4)

Independent capacitor 

The restraint systems control unit (N2/7) has its own capacitor (with enough reserve energy for at least 150 ms), which serves as a fully independent source of energy should this be required in the event of an accident (if the battery is disconnected during a crash).

Short circuit bridges 

When the plug is removed, the short circuit bridges short circuit the squibs in the conventional ignition circuits for the airbags in order to prevent unintended triggering of the squibs due to external influences.