Supplemental Restraint System Control Module (SRS) [2008-2016]: Design

CONTROL MODULE 

Courtesy of VOLVO CARS CORPORATION

The primary task of the supplemental restraint system is to reduce the degree of injury to the driver and passengers in various types of accidents. To do so, the Supplemental Restraint System Module (SRS) analyzes the retardation that arises during a collision and chooses appropriate action.

The control module is aided in its task by internal and external sensors. Based on sensor data, the control module determines whether any of the following should be deployed:

• front airbags
• side impact protection (SIPS) bags
• inflatable curtains
• seat belt tensioners
• adaptive steering column (USA/CDN only)
• adaptive seatbelt force limiter (only XC60 or USA/CDN).

Retardation that exceeds a certain value triggers a calculation that evaluates whether the collision is of sufficient force to deploy any of the protection systems.

The driver and passenger airbags and the seat belt tensioners as well as inflatable curtains are designed to deploy in the event of a frontal collision as necessary. For XC60 or in USA/CDN, the adaptive steering column and the function for adaptive seatbelt force limiting are also activated as necessary.

In case of a side collision, front belt tensioners (presuming the passengers are wearing seat belts) plus the side airbag and inflatable curtain closest to the area of impact are deployed as necessary.

In the event of a rear-end collision, only the front belt tensioners are deployed (presuming the passengers are wearing seat belts).

Supplemental Restraint System Module (SRS) can also register if the vehicle is about to roll over (only XC60). As help for this, the module features a roll-over sensor.

If the vehicle's rotational energy exceeds a certain level, the control module starts a calculation if the roll-over protection is to be deployed. All seatbelt tensioners and inflatable curtains are deployed if roll-over protection is activated.

The Supplemental Restraint System Module (SRS) also has a collision registration function that saves system information in case of a collision. The purpose of this is to enable analysis of collision data for refinement Volvo's collision safety system.

Vehicles on USA/CDN-markets set a non-erasable trouble code in case of a collision that has resulted in activation of a protection system. In these cases the Supplemental Restraint System Module (SRS) must be replaced.

On other markets an erasable code is set in case of a collision. The trouble code can only be erased after collision data has been read out and the memory location has been unlocked. Unlocking means that the memory location once again can be used for storing collision data. When the control module has been involved in four collisions that have resulted in activation of some safety system, a non-erasable trouble code is set. In these cases the Supplemental Restraint System Module (SRS) must be replaced.

In the event of a forceful enough frontal collision, sideways collision or back-end collision, or roll-over (only XC60), a collision signal is transmitted from the Supplemental Restraint System Module (SRS) to the Phone Module (PHM) and the Central Electronic Module (CEM) using a directly connected cable. The purpose of this signal is to:

• switch off the fuel pump (FP)
• switch off the windshield wipers when the car is stationary
• turn off defrosting of windows and rearview mirrors if the vehicle is stationary
• light the interior lighting
• light the flashing hazard lights
• unlock the central locking system
• send an automatic alarm to CSC (Customer Service Center) when an accident has occurred - provided the vehicle is equipped with Volvo On Call (Plus).
• turn off the fuel engine heater

A collision signal is also sent to the Phone Module (PHM) and the Central Electronic Module (CEM) via the Controller area network (CAN).

The Supplemental Restraint System Module (SRS) decides to deploy the airbags and/or the belt tensioners in the event of a frontal collision.

This decision is based on factors such as:

• whether the driver and front passenger are wearing seat belts
• whether the front passenger airbag has been disabled
• the status of the belt buckles
• the status of CAN communication.

Based on the status of the above factors, a low-speed collision could, for example, trigger deployment of the belt tensioner on the driver's side and the airbag on the front passenger side.

Supplemental Restraint System Module (SRS) communicates with Closing Velocity Module (CVM) (only XC60), the main function of which is to prevent or minimize damage in case of frontal collisions.

Vehicles with Closing Velocity Module (CVM) have no front impact sensor. For more information, Refer to: DESIGN  

Closing Velocity Module (CVM) continuously sends information to Supplemental Restraint System module (SRS).

Supplemental Restraint System Module (SRS) uses the information as an early indication if the vehicle is about to collide, and can in this way prepare any actions. Also Closing Velocity Module (CVM) continuously sends information to Supplemental Restraint System Module (SRS) about its status and reliability.

The SRS indicator lamp lights when the ignition is switched on. If no faults are registered by the control module, neither internally nor from the sensors, wiring or igniters, a signal is transmitted via the CAN to the Driver information module (DIM) confirming that the SRS indicator lamp can be switched off. If there is a fault, the Supplemental Restraint System Module (SRS) transmits information to the Driver Information Module (DIM) indicating which lamp should be lit and the text to be displayed in the combined instrument panel:

• The SRS warning lamp
• the general warning lamp or
• the yellow information lamp.

The Driver Information Module (DIM) continuously transmits information to the Supplemental Restraint System Module (SRS) control module via the controller area network (CAN) about the status of the SRS warning lamp.

If for some reason the SRS warning lamp is not operational, the general red warning lamp is used instead.

Note that after a collision, it may be necessary to replace the wiring harness for the components of the protection system which have deployed. This is because the connectors may melt at the moment of deployment. If a connector has melted, the wiring harness adjacent to the connector must be replaced.

FRONT COLLISION SENSOR (NOT XC60) 

Courtesy of VOLVO CARS CORPORATION

The front impact sensors are used to provide the Supplemental Restraint System Module (SRS) with advance information about the collision pulse. This enables the control module to more accurately determine which components to deploy.

The front impact sensors have integrated logic which transmits acceleration data to the Supplemental Restraint System Module (SRS).

In the event of a collision, the control module calculates the acceleration data from the front impact sensors and the internal sensors of the control module to determine if the impact is sufficiently severe to deploy the impact protection.

The control module generates one or more diagnostic trouble codes if one or both of the front impact sensor fail. A diagnostic trouble code is also generated if communication between the control module and either of the front impact sensors fails.

If one (or both) of the front impact sensors stops working for some reason, the control module uses the internal acceleration sensor to determine when to deploy the impact protection.

Data is transmitted on the same cable used for power supply. There is a signal/power supply cable to each front impact sensor and a ground cable.

The front impact sensors are located behind the left and right headlights, respectively.

Each front impact sensor has a specific ID that is used to check that the right front impact sensor is installed in the vehicle.

SIDE IMPACT SENSOR 

Courtesy of VOLVO CARS CORPORATION

The vehicle's side impact sensors are used to provide the Supplemental Restraint System Module (SRS) early information on a side-on collision.

The four sensors used in the car are: 

• 1 side impact sensor in each left and right B post (A)
• 1 side impact sensor in each left and right C post (B)
• 1 side impact sensor (pressure sensor) in each left and right front door (only XC60 or USA/CDN) (C).

The side impact sensors in the B and C posts consist of acceleration sensors that continuously send data to the control module.

The side impact sensors (pressure sensors) in the doors consist of air pressure sensors that continuously transmit data to the control module.

In case of a collision Supplemental Restraint System Module (SRS) uses data from the sensors and from an acceleration sensor, installed internally in the control module, to decide if the collision force is sufficient to active the side impact protection.

Only the side impact protection system nearest the point of impact is deployed.

The control module generates one or more diagnostic trouble codes if one or both of the side impact sensor fail. A diagnostic trouble code is also generated if communication between the control module and either of the side impact sensors fails.

If one (or both) of the side impact sensors stops working for some reason, the control module uses information from the other sensors to determine when to deploy the impact protection.

Data is transmitted on the same cable used for power supply. There is a signal/power supply cable to each side impact sensor and a ground cable.

The four side impact sensors in the B and C posts are of the same type, therefore, they can be installed in all four positions.

The side impact sensors (pressure sensors) in the doors are of the same type and can be installed in either the left or right-hand doors.

Each front impact sensor has a specific ID that is used to check that the right front impact sensor is installed in the vehicle.

ROLL-OVER SENSOR (ONLY XC60) 

Courtesy of VOLVO CARS CORPORATION

The Roll-Over Protection System (ROPS) consists of a roll-over sensor, of the type gyro sensor, which senses the vehicle's angle. The roll-over sensor is used to give Supplemental Restraint System Module (SRS) early information in case of a roll-over.

If the vehicle's sideways angle changes fast enough, then Supplemental Restraint System Module (SRS) will start a calculation how high the rotation energy is. If the rotation energy is high enough, the control module will activate the roll-over protection.

The roll-over protection activates all seatbelt tensioners and inflatable curtains in the vehicle.

In case of incorrect signal from the roll-over sensor, the control module generates a diagnostic trouble code.

The roll-over sensor is installed on the circuit board on Supplemental Restraint System Module (SRS).

SWITCH AIRBAG PASSENGER FRONT (NOT USA/CDN) 

Courtesy of VOLVO CARS CORPORATION

With the switch it is possible to deactivate the airbag for the front 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 key blade in the remote control is used to change the position of the switch.

With the switch in position "OFF", all steps for the airbag are deactivated and the warning light airbag passenger (PAD) is lit.

With the switch in position "ON", the passenger airbag is activated and the warning light activated airbag passenger (PAE) is lit (2008-).

The switch position is determined using two Hall sensors. The Hall sensors for the switch are directly connected to 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) as well as the SRS-warning light are lit and a text message is shown in the Driver Information Module (DIM).

If problems are detected and the passenger airbag cannot be deactivated, then warning light activated airbag passenger (PAE) (2008-) as well as the SRS-warning light are lit instead and a text message is shown in the Driver Information Module (DIM).

OCCUPANT WEIGHT SENSOR (OWS) (USA/CDN ONLY) 

Courtesy of VOLVO CARS CORPORATION

The Occupant Weight Sensor (OWS) consists of three interactive components: 

• Pressure sensor and silicon pad, installed under the seat cushion in passenger seat front.
• The belt tension sensor, mounted in the seat belt lock on the inside of the front passenger seat.
• Occupant weight sensor module, installed under the front passenger seat.

The pressure sensor and silicon pad are linked with a hose. The pressure sensor registers the pressure to which the seat cushion, that is, the silicon pad, is exposed. For example, when someone is sitting in the seat.

Information from the belt tension sensor is also used to ensure the good performance of the system. The belt tension 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 belt tension sensor, the occupant weight sensor performs calculations that give Supplemental Restraint System Module (SRS) the following information:

• Passenger seat empty  - airbag passenger front off  .
• Passenger seat child  - airbag passenger front off  .
• Passenger seat big  - airbag passenger front on  .

The Occupant Weight Sensor (OWS) transmits continuous signals on the internal 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 belt tension sensor is replaced separately.

FRONT AIRBAGS 

Courtesy of VOLVO CARS CORPORATION

The airbags at the front of the vehicle are: 

• driver airbag, 2 stage deployment
• front passenger airbag, 2 or 3-stage deployment.

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

Each airbag stage has a separate igniter component. 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.

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 deployment, 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 deployment, the charge combusts and the gas which develops is blown into the airbag.

The time lapse of the airbag's 2-stage deployment depends on the type of collision and seat belt usage. Both stages are always deployed. In the event of a minor collision, there is a long delay between stages 1 and 2, generating a soft airbag. In the event of a severe collision, there is a short delay between stages 1 and 2, generating a harder airbag.

Stage 3 (front passenger airbag only - USA/CDN) 

Stage 3 of the front passenger airbag is pyrotechnical. Upon deployment, a valve opens on the airbag.

Using information from the seat position sensor, belt buckle sensor and impact sensor, the control module can adjust the inflation volume of the airbag to the severity of the collision. This is done by ventilating the airbag.

ADAPTIVE STEERING COLUMN (USA/CDN ONLY) 

Courtesy of VOLVO CARS CORPORATION

When the impact protection in the adaptive steering column is deployed, a pin is triggered that makes the steering column more deformable. In the event of a severe impact, it will possible to press the steering wheel toward the dashboard to a greater degree than if the steering column were rigid.

Steering is not affected by the deployment of the pin. The pin is deployed by a pyrotechnical charge and is located in the center of the steering column. The impact protection system in the adaptive steering column only deploys if the driver is wearing the seat belt and when the airbag is deployed. The entire steering column must be replaced if the impact protection system in the adaptive steering column has deployed.

SIDE IMPACT AIR BAGS 

Courtesy of VOLVO CARS CORPORATION

There are two side airbags connected to the Supplemental Restraint System Module (SRS). Their connectors are electrically separated from each other. The side airbags are on the outer edge of the front seat backrests, underneath the upholstery. The side airbags are only deployed on the side nearest the point of the impact. Their task is to protect the hips, chest and upper body in the event of a side-on collision.

The side airbags together with the inflatable curtains and other safety systems can help to protect the driver and front passenger in the event of a side-on collision.

The side airbag uses 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.

INFLATABLE CURTAINS 

Courtesy of VOLVO CARS CORPORATION

There are two inflatable curtains connected to the Supplemental Restraint System Module (SRS). Their connectors are electrically separated from each other.

The inflatable curtains are located in the roof between the A-post and C-post. They have only one igniter component each. The purpose of the curtain is to protect the head and parts of the upper body in the event of a side-on collision. The Supplemental Restraint System Module (SRS) deploys the inflatable curtain on the side closest to the point of impact.

The inflatable curtain uses 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 curtain, which falls down and covers the door windows and B-post.

SEATBELT BUCKLE 

Courtesy of VOLVO CARS CORPORATION

The two front seat belt buckles have Hall sensors and are connected to the Supplemental Restraint System Module (SRS). These connections are electrically separated from each other.

In some markets, each rear belt buckle also contains a Hall sensor, which is also connected to the Supplemental Restraint System Module (SRS). These connections are electrically separated from each other.

The Hall sensor detects whether the belt is fastened in the buckle and sends information on belt detection to the Supplemental Restraint System Module (SRS). Information on belt detection is used to adapt the deployment level of airbags and belt tensioners. If a fault is detected in the belt buckles or their connections, there could also be adaption to this depending on the type of fault.

BELT TENSIONERS 

USA/CDN 

Courtesy of VOLVO CARS CORPORATION

Other 

Courtesy of VOLVO CARS CORPORATION

Depending on the market, the vehicle may have up to six belt tensioners. Five of these are located at shoulder height - one for each belt retractor - two in the front (1 and 2) and three in the back seat (3, 4 and 5).

On certain markets there is also a belt tensioner (6) placed in the belt eye located at waist height next to the driver in front. On XC60 there is also, for certain markets, a belt tensioner (6) on the passenger side.

The belt tension contains a pyrotechnical charge that tensions the belt upon deployment.

The belt tensioner tensions the seat belt to reduce the forward movement of the body. This also reduces the forces on the chest from the airbag and seat belt.

The Supplemental Restraint System Module (SRS) determines whether to deploy the respective belt tensioner based on whether the seat belt is in use. The belt tensioner will not be deployed if the seat belt is not fastened. If the seat belts are fastened and seat belt indication in the front seat belt buckles does not function, the belt tensioners will be deployed anyway. Rear belt tensioner deployment is market dependent.

The belt tensioner consists of a pyrotechnical charge and a cylinder with a piston. The piston is connected to a steel cable which is secured to the seat belt retractor. When the control module deploys the belt tensioner, the piston is forced downward by the expanding gas. The piston pulls in the steel cable which retracts the belt.

For USA/CDN: the adaptive belt force limiter, belt retractor, belt retractor sensor and belt tensioner are mounted in a unit. If there is a fault in any of these components, the entire unit must be replaced.

ADAPTIVE SEATBELT FORCE LIMITER (ONLY XC60 OR USA/CDN) 

Courtesy of VOLVO CARS CORPORATION

The adaptive belt force limiters improve the function of the seat belt in the event of a head-on collision that triggers airbag deployment. There are two adaptive belt force limiters in the vehicle. These are integrated in the belt retractors of the driver and front passenger seat and sit at shoulder height. The two adaptive belt force limiters are electrically separated from each other. They have a pyrotechnical charge that upon deployment reduces belt force to reduce the forces against the chest.

The adaptive belt force limiter, belt retractor, belt retractor sensor and belt tensioner are mounted in a unit. If there is a fault in any of these components, the entire unit must be replaced.

BELT RETRACTOR SENSOR 

Courtesy of VOLVO CARS CORPORATION

The belt retractor sensor monitors the status of belt extension.

The belt retractor sensor sends information on the status of belt extension to the control module in real time. The control module then analyzes the obtained values and uses the results so that the belt force limiter can optimize belt force for the person occupying the seat.

There are two belt retractor sensors in the vehicle - one on the driver's side belt retractor and one on the front passenger side belt retractor.

Data is transmitted on the same cable used for power supply. There is a signal/power supply cable for each belt retractor sensor as well as a ground cable.

The adaptive belt force limiter, belt retractor, belt retractor sensor and belt tensioner are mounted in a unit. If there is a fault in any of these components, the entire unit must be replaced.

SEAT POSITION SENSORS (USA/CDN ONLY) 

Courtesy of VOLVO CARS CORPORATION

The seat position sensor can be used to classify whether a small or large person sitting in 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 comprise a Hall sensor that changes current strength based on the position of the seat. The seat position sensor has two classifications - small person or large person. Small person indicates that the seat is approx. 10 cm (4 in) or less from the front-most seat position. All other positions are classified as large person.

For collision purposes, this information is used to optimize the function of adaptive belt force limitation and the front passenger airbag.

SRS INDICATION 

Courtesy of VOLVO CARS CORPORATION

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

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.

FRONT PASSENGER AIRBAG INDICATION (2007) 

Courtesy of VOLVO CARS CORPORATION

In order to indicate the status of the front passenger airbag, the vehicle is equipped with a passenger airbag warning lamp (PAD). The warning lamp is located in the roof console and is directly connected to the Supplemental Restraint System Module (SRS).

The Supplemental Restraint System Module (SRS) turns the warning lamp on or off depending on whether the front passenger airbag is disabled.

If there is a front passenger airbag switch installed (market dependent) and it is used to disable the airbag, the front passenger airbag warning lamp (PAD) lights.

The warning lamp goes out when the airbag is enabled.

If an Occupant Weight Sensor (OWS) is installed (market-dependent), the warning light airbag passenger (PAD) is lit when the airbag is deactivated.

The warning lamp goes out when the airbag is enabled.

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

• malfunction of the switch for the front passenger airbag, causing the Supplemental Restraint System Module (SRS) to disable the front passenger airbag.
• malfunction of the Occupant Weight Sensor (OWS), causing the Supplemental Restraint System Module (SRS) to disable the front passenger airbag.
• other problems that affect function of the SRS-system.

FRONT PASSENGER AIRBAG INDICATION (2008-) 

Courtesy of VOLVO CARS CORPORATION

To indicate status of airbag passenger, the vehicle is equipped with two warning lights. The lights are located in the roof panel and are directly connected to the Supplemental Restraint System Module (SRS)

The Supplemental Restraint System Module (SRS) turns the warning lights on or off depending on whether the front passenger airbag is deactivated or not.

If there is a front passenger airbag switch installed (market-dependent) and it is used to deactivate the airbag, the front passenger airbag warning light (PAD) (1) is lit.

The warning light turns off when the airbag is activated again and then warning light activated airbag passenger (PAE) (2008-) (not USA/CDN) (2) is lit instead.

If an Occupant Weight Sensor (OWS) is installed (market-dependent), the warning light airbag passenger (PAD) is lit when the airbag is deactivated.

The warning light turns off when the airbag is activated again. In these cases, the warning light activated airbag passenger (PAE) (2008-) (not USA/CDN) will never be lit.

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

• malfunction of the switch for the front passenger airbag, causing the Supplemental Restraint System Module (SRS) to disable the front passenger airbag.
• malfunction of the Occupant Weight Sensor (OWS), causing the Supplemental Restraint System Module (SRS) to disable the front passenger airbag.
• other problems that affect function of the SRS-system.

DEPLOYING AIRBAGS/BELT TENSIONERS 

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

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

DEPLOYMENT LEVELS FOR IMPACT PROTECTION UPON HEAD-ON COLLISION 

The table below shows how the SRS system usually reacts in the event of a head-on collision.

Level 1= Low speed collision

Level 5 = Severe collision

Collision level	Front seat		Back seat
	Seat belt not in use	Seat belt in use	Seat belt not in use	Seat belt in use
Level 1	No corrective action.	The belt tensioner is deployed. Airbags are not deployed.	No corrective action.	The belt tensioner is deployed (certain markets only).
Level 2	The airbags are deployed with a slow build-up of pressure.	The belt tensioner is deployed. Airbags are not deployed.	No corrective action.	The belt tensioner is deployed (certain markets only).
Level 3	The airbags are deployed with a slow build-up of pressure.	The belt tensioner is deployed. The airbags are deployed with a slow build-up of pressure. The adaptive steering column is triggered (USA/CDN only). The adaptive belt force limiter could be deployed (USA/CDN).	The belt tensioner is deployed (certain markets only).	The belt tensioner is deployed.
Level 4	The airbags are deployed with a fast build-up of pressure. Airbag ventilation could be triggered (USA/CDN only). The inflatable curtain could be deployed (2008-).	The belt tensioner is deployed. The airbags are deployed with a slow build-up of pressure. The adaptive steering column is triggered (USA/CDN only). The adaptive belt force limiter could be deployed (USA/CDN).	The belt tensioner is deployed (certain markets only).	The belt tensioner is deployed.
Level 5	The airbags are deployed with a fast build-up of pressure. The inflatable curtain could be deployed (2008-).	The belt tensioner is deployed. The airbags are deployed with a fast build-up of pressure. The adaptive steering column is triggered (USA/CDN only). The adaptive belt force limiter could be deployed (USA/CDN). Airbag ventilation (USA/CDN only). The inflatable curtain could be deployed. Airbag ventilation (USA/CDN only).	The belt tensioner is deployed (certain markets only).	The belt tensioner is deployed.

DEPLOYING THE SIDE IMPACT PROTECTION SYSTEM 

The table below shows how the SRS system usually reacts in the event of a side-on collision.

	Side collision, left side	Side collision, right side
Left-hand SIPS bag	X
Left-hand inflatable curtain	X
Right-hand SIPS bag		X
Right-hand inflatable curtain		X
Belt tensioner, front left (only when seat belt is in use)	X	X
Belt tensioner, front right (only when seat belt is in use)	X	X

DEPLOYMENT LEVELS FOR IMPACT PROTECTION UPON REAR-END COLLISION 

The table below shows how the SRS system usually reacts in the event of a rear-end collision.

	Front seat		Back seat
	Seat belt not in use	Seat belt in use	Seat belt not in use	Seat belt in use
Sufficiently large collision level	No corrective action.	The belt tensioner is deployed.	No corrective action.	No corrective action.