Emergency tensioning, Retractor (etr) – Mercedes-Benz BENZ-VEHICLES S 500 User Manual
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• According to accident statistics,
children are safer when properly
restrained in the rear seating
positions than in the front seating
positions.
• Children too big for child restraint
systems should ride in rear seats
using regular seat belts. Position
shoulder belt across chest and
shoulder, not face or neck. A
booster seat may be necessary to
achieve proper belt positioning.
• Adjust the front passenger seat as
far as possible rearward from the
dashboard when a child restraint
is installed.
Supplemental Restraint System
(SRS)
The SRS uses two crash severity levels
(thresholds) to activate either the ETR
or airbag or both. Activation depends
on exceeding the thresholds and
fastening of the seat belt.
Seat belt fastened
• first threshold exceeded:
ETR activates
• second threshold exceeded:
airbag also activates
Seat belt not fastened
• first threshold exceeded:
airbag activates, but not ETR
Driver and front passenger systems
operate independently from each other.
Emergency Tensioning Retractor
(ETR)
The seat belts for the front seats are
equipped with emergency tensioning
retractors. These tensioning retractors
are located in each belt's inertia reel and
become operationally ready with the
key in steering lock position 1 or 2.
The emergency tensioning retractors
are designed to activate only when the
seat belts are fastened during frontal
and front-angled impacts exceeding the
first threshold of the SRS. They remove
slack from the belts in such a way that
the seat belts fit more snugly against
the body restricting its forward
movement as much as possible.
In cases of other frontal impacts,
roll-overs, certain side impacts, rear
collisions, or other accidents without
frontal forces, the emergency
tensioning retractors 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
retractor safety guidelines see Safety
Guidelines in Index.