Supplemental restraint system (SRS), function - GF91.60-P-0002PMA

MODELS 203.0 /2 as of 1.6.04, 203.7 as of 24.4.04 with CODE (494a) USA version 

Deployment characteristics shown on Model 203.0 

General 

The supplemental restraint system (SRS) is used to provide passive interior protection. The following events can be recorded and differentiated:

• Head-on collision
• Rear-end collision
• Side-on collision

If an accident occurs the relevant airbags and emergency tensioning retractors are triggered, depending on the severity of the detected collision. The following safety devices can be triggered if an accident occurs, depending on the configuration of the vehicle:

• Driver airbag
• Passenger airbag
• Driver sidebag
• Front passenger sidebag
• Right rear side airbag
• Left rear side airbag
• Emergency belt tensioner for driver
• Emergency belt tensioner for front passenger
• Left rear emergency belt tensioner
• Right rear emergency belt tensioner
• Right window airbag
• Left window airbag

The system monitors itself continuously and notifies the driver of faults immediately via the multifunction display (A1p13) in the instrument cluster (A1). Any faults are stored in the non-volatile memory of the restraint systems control unit (N2/7). The system has a capacitor in the restraint systems control unit (N2/7). If the battery is disconnected the entire system is powered for at least 150 ms.

Function requirements 

• Circuit 15R ON
• Circuit 15 ON

System monitoring 

After successful self-test the system continuously monitors the inputs and outputs of the restraint systems control unit (N2/7). System malfunctions are indicated by the airbag indicator and warning lamp (A1e15) in the multifunction display (A1p13) in the instrument cluster (A1). In order to do this the instrument cluster (A1) receives the relevant message from the restraint systems control unit (N2/7) via the Controller Area Network Bus Class B (interior) (CAN-B).

Sensors 

• Sidebag and windowbag sensor, left (A53/1)
• Sidebag and windowbag sensor, right (A54/1)
• Driver seat belt buckle restraint systems switch (S68/3)
• Front passenger seat belt buckle restraint systems switch (S68/4)
• Driver-side frontal acceleration sensor (B48/1)
• Passenger-side frontal acceleration sensor (B48/2)

Seat occupied recognition sensor 

If the front passenger airbag is triggered by the restraint systems control unit (N2/7) the data received from the WSS (Weight Sensing System) control unit (N2/13) via the CAN-B and the switching statuses of the driver seat belt buckle restraint systems switch (S68/3) and the front passenger seat belt buckle restraint systems switch (S68/4) are also taken into consideration. Under certain circumstances (e.g. certified child seat detected or front passenger seat unoccupied) the restraint systems control unit (N2/7) prevents the airbag and emergency tensioning retractor unit at the front passenger side from being triggered. The function of the child seat recognition system and the deactivation of the front passenger airbag by the child seat recognition system are indicated by the Automatic child seat recognition airbag OFF indicator lamp (N72/1e1).

The airbag units bear the label "SRS Airbag" at their installation location.

Diagnosis 

Diagnosis takes place using STAR DIAGNOSIS.

Automatic emergency opening of the central locking (CL) system 

A crash sensor is integrated in rear SAM control unit with fuse and relay module (N10/2) If the vehicle is accelerated > 60 m/sec.² an unlocking signal is transmitted to the relevant door control unit after a delay of 8 to 11 seconds by the rear SAM control unit with fuse and relay module (N10/2) and executed.

The following control units receive the emergency opening system:

• Left front door control module (N69/1)
• Right front door control module (N69/2)
• Left rear door control unit (N69/3) (except model 203.7)
• Right rear door control unit (N69/4) (except model 203.7)

Flashing alarm 

In the event of a crash, the hazard warning system is switched on automatically. The restraint systems control unit (N2/7) transmits the crash signal to the rear SAM control unit with fuse and relay module (N10/2) via the CAN-B. In this case the rear SAM control unit with fuse and relay module (N10/2) acts as master and cyclically places the turn signal on the CAN-B for the duration of the request. The message is received by the front SAM control unit with fuse and relay module (N10/1), the left front door control unit (N69/1) and the right front door control unit (N69/2) and used to actuate the relevant turn signals. The message is read in by the upper control panel control unit (N72/1) and the instrument cluster (A1) in order to provide the driver with optical and acoustic feedback. The hazard warning system can be switched off at any time using the hazard warning system switch (N72/1s5).

Emergency call telegram 

The restraint systems control unit (N2/7) transmits (with code (359) TELE AID emergency call system, low-cost) a crash signal to the emergency call system control unit (N123/4) via a discrete line, irrespective of the severity of the accident.

The emergency call system control unit (N123/4) automatically transmits an SMS to the responsible control center containing the following emergency data:

• Vehicle position, direction of travel and history
• Vehicle data (e.g. circuit status)
• Crash detection (severity of accident)
• Customer data (telephone number)

	Supplemental restraint system (SRS), block diagram		GF91.60-P-0002-03PMA
	Supplemental Restraint System (SRS) Deployment Logic		GF91.60-P-0002-08PMA
	Rear-End Collision - Function		GF91.60-P-2004PMA
	Side impact protection system function		GF91.60-P-2005PMA
	Head-On Collision - Function		GF91.60-P-2006PMA