Subaru Legacy BN/BS (2015-2019) Owners Manual: SRS side airbag and SRS curtain airbag operation

The following airbags deploy independently of each other because each has its own impact sensor.

•  Driver's SRS side airbag
•  Front passenger's SRS side airbag
•  SRS curtain airbag (right-hand side)
•  SRS curtain airbag (left-hand side)

Therefore, they may not both deploy in the same accident. Also, the SRS side airbag deploys independently of the driver's and front passenger's SRS frontal airbags in the steering wheel and instrument panel.

An impact sensor, which senses impact force, is located in each of the following locations.

•  In the left and right front doors
•  In the left and right center pillars
•  In the left and right rear wheel houses
•  In the airbag control module
•  In the left and right front fenders (only SRS curtain airbags are designed to deploy when the front sub sensors sense a severe impact.)

A rollover sensor is also located inside the airbag control module.

If both of the following sensors together sense an impact force above a predetermined level in a side collision, the control module causes both the SRS side airbag and curtain airbag on the impacted side to inflate regardless of whether the rear wheel house impact sensor on the same side senses an impact.

•  the impact sensor that is located in the airbag control module
•  one of the center pillar impact sensors or front door impact sensors

If both of the following sensors together sense an impact force above a predetermined level in a side collision, the control module causes only the SRS curtain airbag on the impacted side to inflate.

•  the impact sensor that is located in the airbag control module
•  one of the rear wheel house impact sensors

Even if a frontal collision occurs, both right and left SRS curtain airbags will deploy when the front sensor and the control unit determine that the impact results from an offset frontal collision.

The SRS curtain airbags are designed to deploy under the following conditions.

•  The driver's SRS frontal airbag deploys or the driver's and passenger's SRS frontal airbags deploy in a frontal collision.
•  The system determines that the collision is an offset frontal collision.
•  The vehicle is in an extremely inclined state such as during a rollover.

The SRS curtain airbags are basically not designed to deploy in the following cases.

•  In a frontal collision when the SRS frontal airbags do not deploy or the system determines that the collision is other than an offset frontal collision
•  In most lesser inclined states

If the rollover sensor detects rollover of the vehicle, the control module inflates the SRS curtain airbags. At this time, the driver's and front passenger's seatbelt pretensioners also operate at the same time.

After the deployment, the SRS side airbag immediately starts to deflate. The time required from detection of an impact to deflation of an SRS side airbag after deployment is shorter than the blink of an eye.

The SRS curtain airbag remains inflated for a while following deployment then slowly deflates.

The SRS side airbag and SRS curtain airbag deploy even when no one occupies the seat on the side on which an impact is applied.

The SRS side airbag and SRS curtain airbag are designed as follows:

•  to deploy in the event of an accident involving a moderate to severe side impact collision
•  to function on a one-time-only basis.

The SRS side airbag and SRS curtain airbag are not designed to deploy in the following cases:

•  in most lesser side impacts
• in most rear impacts (because the SRS side airbag and SRS curtain airbag deployment would not protect the occupant in those situations)

The SRS side airbag and SRS curtain airbag deployment depend on the level of force experienced in the passenger compartment during a side impact collision.

That level differs from one type of collision to another, and it may have no bearing on the visible damage done to the vehicle itself.

Example of the type of accident in which the SRS side airbag will most likely deploy

A severe side impact near the front seat or the rear seat.

Examples of the types of accidents in which the SRS curtain airbag will most likely deploy

1. The vehicle is involved in a severe side impact near the front seat or the rear seat.
2.  The vehicle rolls onto its side or the roof.
3.  The angle of vehicle tip-up is marginal or the skidding vehicle's tires hit a curbstone laterally.
4.  An offset frontal collision that is severe enough to deploy the front airbag.

Examples of the types of accidents in which it is possible that the SRS curtain airbag will deploy

1. Hitting a curb, edge of pavement or hard surface
2.  Falling into or jumping over a deep hole
3.  Landing hard or vehicle falling

It is possible that the SRS curtain airbags will deploy if a serious impact occurs to the underside of your vehicle. Some examples are shown in the illustration.

Examples of the types of accidents in which the SRS side airbag is unlikely to deploy

1. The vehicle is involved in an oblique side-on impact.
2.  The vehicle is involved in a side-on impact in an area outside the vicinity of the passenger compartment.
3.  The vehicle strikes a telephone pole or similar object.
4.  The vehicle is involved in a side-on impact from a motorcycle.
5.  The vehicle rolls onto its side or the roof.

There are many types of collisions which might not necessarily require SRS side airbag deployment. In the event of accidents like those illustrated, the SRS side airbag may not deploy depending on the level of accident forces involved.

Examples of the types of accidents in which the SRS curtain airbag is unlikely to deploy

1. The vehicle is involved in an oblique side-on impact.
2.  The vehicle is involved in a side-on impact in an area outside the vicinity of the passenger compartment.
3.  The vehicle strikes a telephone pole or similar object.
4.  The vehicle is involved in a side-on impact from a motorcycle.

There are many types of collisions which might not necessarily require SRS curtain airbag deployment. In the event of accidents like those illustrated, the SRS curtain airbag may not deploy depending on the level of accident forces involved.

Examples of the types of accidents in which the SRS side airbag and SRS curtain airbag is not designed to deploy in most cases

1. The vehicle is involved in frontal collision with another vehicle (moving or stationary).

   (Only the SRS side airbag is designed not to deploy in most cases)

2.  The vehicle is struck from behind.
3.  The vehicle pitches end over end.

In the event of accidents like those illustrated, the SRS side airbag and SRS curtain airbag are not designed to deploy in most cases.

1. First impact
2.  Second impact
1. SRS curtain airbag
2.  SRS side airbag

In an accident where the vehicle is struck from the side more than once, the SRS side airbag and SRS curtain airbag deploy only once on the first impact.

Example: In the case of a double side impact collision, first with one vehicle and immediately followed by another from the same direction, once the SRS side airbag and SRS curtain airbag are activated on the first impact, they will not be activated on the second.