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60Restraint systems
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Supplemental restraint system (SRS)
Airbags are intended as a supplement to seat belts.
Airbags alone cannot protect as well as airbags plus
seat belts in impacts for which the airbags were
designed to operate, and do not afford any protection
whatsoever in crashes for which the airbags are not
designed to deploy.
The SRS uses two crash severity levels (thresholds) to
activate either the Emergency tensioning device or front
airbag or both. Activation depends on the direction and
severity of the impact exceeding the preset thresholds
and whether the seat belt is fastened.
Seat belt fastened
• first threshold exceeded: ETD activates
• second threshold exceeded: airbag also activates
Seat belt not fastened
• first threshold exceeded:
airbag activates, but not ETD
Driver and front passenger systems operate
independently of each other.
Emergency tensioning device (ETD)
The seat belts for the front seats are equipped with
Emergency tensioning devices. These tensioning
devices are located in each belt’s inertia reel and
become operationally ready with the electronic key in
steering lock position 1 or 2.
The Emergency tensioning devices are designed to
activate only when the seat belts are fastened during
frontal impacts exceeding the first threshold of the SRS
and in rear impacts exceeding a preset severity level.
They remove slack from the belts in such a way that the
seat belts fit more snugly against the body restricting its
forward Emergency tensioning device movement as
much as possible.
In cases of other frontal impacts, angled impacts,
roll-overs, certain side impacts, or other accidents
without sufficient frontal or rear impact forces, the
Emergency tensioning device will not be activated. The
driver and passengers will then be protected by the
fastened seat belts and inertia reel in the usual manner.
For seat belt and Emergency tensioning device safety
guidelines see page 67.