Part 2

Seat position sensors (USA/CDN only)

The seat position sensor is used to determine the size of the person sitting on the seat. There are two seat position sensors in the vehicle, one under the driver's seat and one under the front passenger seat. The seat position sensors are directly connected to the supplemental restraint system module (SRS). The seat position sensors have separate signal cables to the control module and a common ground.

The seat position sensor consists of a Hall sensor which modifies the current depending on the position of the seat. The seat position sensor has two classifications, these are a small person and a large person. A small person means that the seat is approximately 10 cm from the first seat position and forwards. Other positions are classified as a large person. This information is used by the function for adaptive seatbelt force limiting.

Switch on/off, front passenger airbag (not USA/CDN)

With the switch it is possible to activate or deactivate the airbag for the front seat passenger.
The switch is located on the side of the instrument panel, on the passenger side. The switch is only accessible when the front side door on the passenger side is open.
The ignition key is used to change the position of the switch. When the switch is in position "OFF", both steps for the passenger airbag are deactivated and warning light airbag passenger (PAD) is lit.
When the switch is in position "ON", the passenger airbag is activated and warning light activated airbag passenger (PAE) is lit.
When the switch position is moved between "OFF" and "ON", two Hall sensor sense in which position the switch is. The Hall sensors for the switch are directly connected to the Supplemental restraint system module (SRS).
Each Hall sensor is separately connected to the control module. The signal that is sent from the Hall sensors consists of two different current levels depending on which position the switch is in.

If the signal from the Hall sensor cannot be interpreted correctly, a diagnostic trouble code is generated and the control module may, depending on the problem, choose to deactivate the passenger airbag.
If the passenger airbag is deactivated then warning light airbag passenger (PAD) and SRS-warning light are lit, and a text message is shown in the Driver information module (DIM). If a problem is detected and the passenger airbag is not deactivated, instead warning light activated airbag passenger (PAE) and the SRS-warning light are lit, and a text message is shown in the Driver information module (DIM).

NOTE: The activating switch, on/off, for the front passenger airbag and occupant weight sensor (OWS) must not be installed in the vehicle together.

Occupant weight sensor (OWS) (USA/CDN only)

The occupant weight sensor (OWS) consists of three interactive components:

- The pressure sensor, installed under the front passenger seat.
- Belt force sensor, mounted in the seat frame on the outside of the front passenger seat.
- Occupant weight sensor module, installed under the front passenger seat.

The pressure sensor and occupant weight sensor are linked via a hose. The pressure sensor registers the pressure the seat cushion is exposed to, for example when someone is sitting in the seat. Information from the seat belt force sensor is also used to ensure the good performance of the system. The seatbelt force sensor informs the occupant weight sensor module what force the belt is tensioned with.This is done because the pressure measured by the pressure sensor can be affected by the passenger fastening the seatbelt tightly.This means that the passenger exerts greater pressure on the seat than during normal seatbelt use. The passenger is then interpreted as being heavier than he or she is.
Using information from both the pressure sensor and the seat belt force sensor, the occupant weight sensor module carries out calculations and classifications of what is affecting the system. This forms the basis for the recommendation that is communicated to the supplemental restraint system.
The occupant weight sensor (OWS) transmits continuous signals on the local controller area network (CAN), which the supplemental restraint system module (SRS) and occupant weight sensor (OWS) are connected to. If the occupant weight sensor (OWS) does not function correctly the supplemental restraint system module (SRS) will:

- disable the front passenger airbag
- light the passenger airbag warning lamp (PAD) in the roof console
- light the SRS (supplemental restraint system) warning lamp and display the alert message in the driver information module (DIM).

If a fault occurs in any of the components the following should be noted:

- The pressure sensor and occupant weight sensor module must be replaced at the same time
- The seat belt force sensor is replaced separately.

NOTE: The activating switch, on/off, for the front passenger airbag and occupant weight sensor (OWS) must not be installed in the vehicle together.

Adaptive seatbelt force limiter (USA/CDN only)

WARNING: Never use an ohmmeter or similar tool to test airbags, door mounted inflatable curtains, adaptive seat belt tensioners, the adaptive steering column, rollover bar cassette or seat belt tensioners. Disconnect airbags, door mounted inflatable curtains, adaptive seat belt tensioners, adaptive steering column, rollover bar cassette or seat belt tensioners before testing them. Failure to do so may result in accidental deployment. This could result in serious injury or death.

The airbags at the front of the vehicle are:

- driver airbag, 2 stage deployment
- front passenger airbag, 2 stage deployment.

The driver's airbag is located in the steering wheel. The passenger airbag is located above the glove compartment in the dashboard.

The front airbags have two ignition components each. These are electrically separated from each other. This means that the different ignition components have their own separate power supply and grounding points from the control module. Two power supply outputs are required from the control module for each airbag, one for each ignition component. This means that in total four pins on the control module, two power supply pins and two ground pins, are used for each airbag.

During airbag deployment, electrical signals are transmitted from the supplemental restraint system module (SRS) to the relevant airbag stage.

Stage 1
Stage 1 of the driver s airbag is pyrotechnic. In the event of activation the charge combusts and the gas which develops is blown into the airbag. Stage 1 on the passenger airbag consists of a pyrotechnic component in combination with a reservoir which stores a gas. In the event of deployment, the pyrotechnic charge combusts and mixes with the stored gas. The gas mixture inflates the airbag.

Stage 2
Stage 2 of the driver s and passenger airbags is pyrotechnical. In the event of activation the charge combusts and the gas which develops inflates the airbag. The pace of the airbag 2 stage activation is dependent on the collision type and seat belt use. Both stages always activate. The difference is that in the event of a lesser impact, there is a greater time delay between stage 1 and stage 2. For more serious impacts the time delay is shorter between stages 1 and 2, which gives a stiffer airbag.

WARNING: Never use an ohmmeter or similar tool to test airbags, door mounted inflatable curtains, adaptive seat belt tensioners, the adaptive steering column, rollover bar cassette or seat belt tensioners. Disconnect airbags, door mounted inflatable curtains, adaptive seat belt tensioners, adaptive steering column, rollover bar cassette or seat belt tensioners before testing them. Failure to do so may result in accidental deployment. This could result in serious injury or death.

Side impact air bags

WARNING: Never use an ohmmeter or similar tool to test airbags, door mounted inflatable curtains, adaptive seat belt tensioners, the adaptive steering column, rollover bar cassette or seat belt tensioners. Disconnect airbags, door mounted inflatable curtains, adaptive seat belt tensioners, adaptive steering column, rollover bar cassette or seat belt tensioners before testing them. Failure to do so may result in accidental deployment. This could result in serious injury or death.

The retractable roof has a lower level of protection than a vehicle with a fixed roof. ROPS (Roll Over Protection System) is available to sufficiently protect the passengers in the event of the vehicle rolling over. The system consists of two roll-over bars and sensors in the Supplemental restraint system module (SRS). The roll-over bars are integrated in a cassette and the entire roll-over bar cassette must be replaced if replacing the roll-over bars. Both roll-over bar cassettes are installed between the body plates behind the rear seat backrest. The roll-over bar cassettes are directly connected to the Supplemental restraint system module (SRS).
The sensors for roll-over are installed in the Supplemental restraint system module (SRS) and the entire control module must be replaced if replacing a sensor.

The system is normally inactive and is only activated when the vehicle rolls. In this case, the roll-over bar cassettes and the seat belt tensioners and the door mounted inflatable curtains activate as well.

WARNING: Never use an ohmmeter or similar tool to test airbags, door mounted inflatable curtains, adaptive seat belt tensioners, the adaptive steering column, rollover bar cassette or seat belt tensioners. Disconnect airbags, door mounted inflatable curtains, adaptive seat belt tensioners, adaptive steering column, rollover bar cassette or seat belt tensioners before testing them. Failure to do so may result in accidental deployment. This could result in serious injury or death.

SRS indication

The supplemental restraint system module (SRS) continuously checks the system. A diagnostic trouble code (DTC) is stored and an SRS indication is made.
SRS indication is accompanied by a text message in the Driver information module (DIM), partly through:

- an SRS warning lamp
- a general warning lamp
- a yellow information lamp.

The lamps light depending on how serious the fault is: Information about which lamp should be lit is transmitted by the supplemental restraint system module (SRS) on the controller area network (CAN).

The SRS warning lamp lights when the ignition is switched on. If no faults are registered by the control module, either internally or from the sensors, wiring or igniters, a signal is transmitted on the controller area network (CAN) to the driver information module (DIM) confirming that the SRS warning lamp can be switched off. If no faults are detected when the ignition is switched on, the lamp will remain lit for a few seconds. The lamp goes out when the system has been checked and is operating without faults.

The control module has an EEPROM memory which retains data about diagnostic trouble codes (DTCs) even when the battery has been disconnected.

The driver information module (DIM) continuously indicates to the supplemental restraint system module (SRS) the function of the SRS warning lamp. If the lamp stops working, the general warning lamp lights up and a message is displayed.

NOTE: If a diagnostic trouble code is stored because the resistance in an ignition cable is too high or too low, it is important that the resistance of the ignition cable is not measured when the collision protection system is connected. Special tools with the same resistance as the collision protection system must be used for troubleshooting.

Passenger airbag indication

Supplemental restraint system module (SRS) sends signals on the CAN-net to Central electronic module (CEM) about the airbag for passenger front is activated or not.
If Central electronic module (CEM) receives information that passenger airbag is activated, it sends signals on a directly connected cable to light warning light activated airbag passenger (PAE) (1).
It works in the same way if Central electronic module (CEM) receives information that the passenger airbag is deactivated, but then the signal to light the warning light airbag passenger (PAD) (2) is sent.
The lights are located in the overhead panel. Each light is on until Central electronic module (CEM) receives information that status of the passenger airbag has been changed.

Depending on the market, if the switch for activating and deactivating the front passenger airbag is used to deactivate it, the passenger airbag disconnected (PAD) warning lamp lights.
The warning light goes off when the airbag is activated again and then warning light activated passenger (PAE) is lit instead.

If an occupant weight sensor (OWS) is installed (market-dependent), the passenger airbag warning light (PAD) lights when the airbag is deactivated. The warning lamp goes out when the airbag is enabled.

If Occupant weight sensor (OWS) is installed, there is no warning light activated airbag passenger (PAE) installed.

Reason the passenger airbag warning lamp (PAD) lights could also be:

- communication problems between the supplemental restraint system module (SRS) and central electronic module (CEM)
- faulty function in the on/off switch for the front passenger airbag
- defective occupant weight sensor (OWS) function.

Seatbelt buckle

The two front seat belt buckles have Hall sensors and are connected to the SRS module. These connections are electrically separated from each other.

The Hall sensor detects whether the belt is engaged in the seat belt buckle or not and indicates this to the supplemental restraint system module (SRS). The information is used to set the activation level for airbags and seat belt tensioners. If a fault is detected in the seat belt buckles or in their terminals, an adjustment is made for this, depending on the type of fault.
The rear seat belt buckles can be connected (market dependent) to the central electronic module (CEM) which then transmits the status of the seat belt buckles to the SRS (supplemental restraint system) module via the controller area network (CAN). In the event of a fault in the rear seat belt buckles the seat belt tensioners will function as if the seatbelts are fastened (market dependent).

Activating airbags/seat belt tensioners

The collision safety system is extremely advanced. It is able to adapt airbag deployment and the activation of the seat belt tensioners to suit the specific circumstances of a collision. In general it is extremely unlikely that all airbags and seat belt tensioners will be deployed in the same accident. It is possible that only one airbag or seat belt tensioner is deployed. This is determined by the supplemental restraint system module (SRS) based on the forces that occur during the collision.

If the control module deploys the front airbags, both stages will always be activated. By varying the time between the two deployment phases, the inflation of the airbag is more gentle for a low speed collision.

Deployment levels for airbags/seat belt tensioners

The table below shows how the SRS system activates the protection system as necessary in the event of a frontal impact.

Level 1 = Low speed collision
Level 5 = Severe collision

Deploying the side impact protection system

The table below shows how the SRS system activates the protection system as necessary in the event of a side impact.

Activating the collision protection system

The table below shows how the SRS system activates the protection system as necessary in the event of a rear impact.