Subaru Legacy BN/BS (2015-2019) Owners Manual: SUBARU advanced frontal airbag operation

1. Driver's side
2.  Passenger's side

The SUBARU advanced frontal airbag system is designed to determine the activation or deactivation condition of the front passenger's SRS frontal airbag depending on the total load on the front passenger's seat monitored by the front passenger's occupant detection system weight sensor. For this reason, only the driver's SRS frontal airbag may deploy in the event of a collision, but this does not mean failure of the system.

If the front sub sensors inside both front fenders and the impact sensors in the airbag control module detect a predetermined amount of force during a frontal collision, the control module sends signals to the airbag module(s) (only driver's module or both driver's and front passenger's modules) instructing the module(s) to inflate the SRS frontal airbag(s). The driver's and front passenger's SRS frontal airbags use dual stage inflators. The two inflators of each airbag are triggered either sequentially or simultaneously, depending on the severity of impact in the case of the driver's SRS frontal airbag and depending on the severity of impact and the total load on the seat in the case of the front passenger's SRS frontal airbag.

After deployment, the SRS airbag immediately starts to deflate so that the driver's vision is not obstructed and the driver's ability to maintain control of the vehicle is not impaired. The time required from detecting impact to the deflation of the SRS airbag after deployment is shorter than the blink of an eye.

The driver's and front passenger's seatbelt pretensioners operate at the same time in both of the following cases.

•  When only the driver's SRS frontal airbag deploys
•  When driver's and front passenger's SRS frontal airbags deploy

The driver's SRS frontal airbag and front passenger's SRS frontal airbag are designed to deploy in the event of an accident involving a moderate to severe frontal collision. They are not designed to deploy in most lesser frontal impacts because the necessary protection can be achieved by the seatbelt alone. Also, they are not designed to deploy in most side or rear impacts or in most rollover accidents because deployment of these airbags would not help the occupant in those situations. The driver's and front passenger's SRS frontal airbags are designed to function on a one-time-only basis.

SRS airbag deployment depends on the level of force experienced in the passenger compartment during a 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.

 Examples of accident in which the driver's/driver's and front passenger's SRS frontal airbag(s) will most likely deploy

A head-on collision against a thick concrete wall at a vehicle speed of 12 to 19 mph (20 to 30 km/h) or higher activates only the driver's SRS frontal airbag or both driver's and front passenger's SRS frontal airbags. The airbag(s) will also be activated when the vehicle is exposed to a frontal impact similar in fashion and magnitude to the collision described above.

 Examples of the types of accidents in which it is possible that the driver's/driver's and front passenger's SRS frontal airbag(s) will deploy

Only the driver's SRS frontal airbag or both driver's and front passenger's SRS frontal airbags may be activated when the vehicle sustains a hard impact in the undercarriage area from the road surface (such as when the vehicle plunges into a deep ditch, is severely impacted or knocked hard against an obstacle on the road such as a curb).

Examples of the types of accidents in which deployment of the driver's/driver's and front passenger's SRS frontal airbag(s) is unlikely to occur

1. The vehicle strikes an object, such as a telephone pole or sign pole
2.  The vehicle slides under the load bed of a truck.
3.  The vehicle sustains an oblique offset frontal impact.
4.  The vehicle sustains an offset frontal collision.
5.  The vehicle strikes an object that can move or deform, such as a parked vehicle.

There are many types of collisions which might not necessarily require deployment of driver's/driver's and front passenger's SRS frontal airbag(s). In the event of accidents like those illustrated, the driver's/ driver's and front passenger's SRS frontal airbag(s) may not deploy depending on the level of accident forces involved.

Examples of the types of accidents in which the driver's/driver's and front passenger's SRS frontal airbag(s) is not designed to deploy in most cases

The driver's and front passenger's SRS frontal airbags are designed not to deploy in most cases if the vehicle is struck from the side or from behind, or if it rolls onto its side or roof, or if it is involved in a lowspeed frontal collision.

1. First impact
2.  Second impact

In an accident where the vehicle is impacted more than once, the driver's and/or front passenger's SRS frontal airbag(s) will deploy only once on the first impact.

Example: In the case of a double collision, first with another vehicle, then against a concrete wall in immediate succession, once either or both of the driver's and front passenger's SRS frontal airbags is/are activated on the first impact, it/they will not be activated on the second impact.