Function

Function

Checking the SRS system




When the ignition key is turned from 0 to II or III, the status of the internal functions in the supplemental restraint system module (SRS) (4/4) is checked, as well as all directly connected components such as:
- airbag driver (8/3)
- airbag passenger (8/4)
- seat belt tensioners (8/10 and 8/11)
- front seat belt buckles (3/60 and 3/61)
- side impact sensors (7/73, 7/74, 7/75 and 7/76)
- inflatable curtains (8/39 and 8/40)
- side impact protection (SIPS) bags (8/33 and 8/34).
At the same time the Supplemental Restraint System Module (SRS) transmits a signal to the combined instrument panel (5/1) which lights the SRS indicator lamp. The SRS indicator lamp is lit while the SRS system is being checked. When the SRS system has been tested and if no faults have been detected, the SRS indicator lamp goes out.
If a fault is identified, the SRS indicator lamp in the combined instrument panel remains lit.

Function in the event of a frontal impact




In event of a frontal collision the retardation of the two acceleration sensors in the control module is registered. This sets the deployment level of the actions to be carried out. From the deployment level the Supplemental Restraint System Module (SRS) deploys one or more of the following components:
- airbag driver (8/3)
- airbag passenger (8/4)
- seat belt tensioner driver (8/10)
- seat belt tensioner passenger (8/11).
For further information, see Design Design.
A collision signal is transmitted on a direct connection from the Supplemental Restraint System Module (SRS) (4/4) to the central electronic module (CEM) ( 4/39) when the collision protection system is activated. The VGLA (Volvo guard lock and alarm system) module ensures that the central locking system unlocks.

Side impact




In event of a side-on collision, the side impact sensors in the left (7/73 and 7/75) and right-hand (7/74 and 7/76) sides evaluate the force of the collision pulse. If the damage is sufficiently great a trigger pulse to activate the collision protection system is sent to the control module (4/4). The control module also requires a confirmation signal, either from the acceleration sensors in the control module or from another side impact sensor. If the pulse from the collision sensor and side impact sensors meets the conditions for activation of the side impact protection (SIPS) bags (8/33 and 8/34) and/or inflatable curtains (8/39 and 8/40), the collision sensor deploys the side impact protection (SIPS) bags or inflatable curtains. The side impact protection (SIPS) bags normally only deploy on the side of the impact.
Information about the collision is stored in the control module and the side impact sensor and can be read off at a later time.