2003 LINCOLN TOWN CAR crash sensor

SAFETY RESTRAINTS
Personal Safety System
The Personal Safety System provides an improved overall level of frontal
crash protection to front seat occupants and is designed to help further
reduce the risk of air bag-related injuries. The system is able to analyze
different occupant conditions and crash severity before activating the
appropriate safety devices to help better protect a range of occupants in
a variety of frontal crash situations.
Your vehicle’s Personal Safety System consists of the following items:
•Driver and passenger dual-stage air bag supplemental restraints
•Driver and front passenger side air bags
•Front safety belts with pretensioners, energy management retractors,
and safety belt usage sensors
•Driver’s seat position sensor
•Passenger occupant classification sensor
•Front crash severity sensor
•Restraints Control Module (RCM) with impact and safing sensors
•Restraint system warning light and back-up tone
•The electrical wiring for the air bags, crash sensor(s), safety belt
pretensioners, front safety belt usage sensors, driver seat position
sensor, passenger occupant classification sensor, and indicator lights
How does the personal safety system work?
The Personal safety system can adapt the deployment strategy of your
vehicle’s safety devices according to crash severity and occupant
conditions. A collection of crash and occupant sensors provides
information to the Restraints control module (RCM). During a crash, the
RCM activates the safety belt pretensioners and/or either one or both
stages of the dual-stage air bag supplemental restraints based on crash
severity and occupant conditions.
The fact that the pretensioners or air bags did not activate for both front
seat occupants in a collision does not mean that something is wrong with
the system. Rather, it means the Personal safety system determined the
accident conditions (crash severity, belt usage, etc.) were not
appropriate to activate these safety devices. Front air bags and
pretensioners are designed to activate only in frontal and near-frontal
collisions, not rollovers, side-impacts, or rear-impacts unless the collision
causes sufficient longitudinal deceleration.
2003 Town Car(tow)
Owners Guide (post-2002-fmt)
USA English(fus)
Seating and Safety Restraints
133

Driver and passenger dual-stage air bag supplemental restraints
The dual-stage air bags offer the capability to tailor the level of air bag
inflation energy. A lower, less forceful energy level is provided for more
common, moderate-severity impacts. A higher energy level is used for
the most severe impacts. Refer toAir bag supplemental restraints
section in this chapter.
Front crash severity sensor
The front crash severity sensor enhances the ability to detect the
severity of an impact. Positioned up front, it provides valuable
information early in the crash event on the severity of the impact. This
allows your Personal safety system to distinguish between different levels
of crash severity and modify the deployment strategy of the dual-stage
air bags and safety belt pretensioners.
Driver’s seat position sensor
The driver’s seat position sensor allows your Personal safety system to
tailor the deployment level of the driver dual-stage air bag based on seat
position. The system is designed to help protect smaller drivers sitting
close to the driver air bag by providing a lower air bag output level.
Passenger occupant classification sensor (OCS)
For air bags to do their job they must inflate with great force, and this
force can pose a potentially deadly risk to occupants that are very close
to the air bag when it begins to inflate. For some occupants, this occurs
because they are initially sitting very close to the air bag. For other
occupants, this occurs when the occupant is not properly restrained by
seat belts or child safety seats and they move forward during pre-crash
braking. The most effective way to reduce the risk of unnecessary
injuries is to make sure all occupants are properly restrained. Accident
statistics suggest that children are much safer when properly restrained
in the rear seating positions than in the front.
Air bags can kill or injure a child in a child seat.NEVERplace a
rear-facing child seat in front of an active air bag. If you must
use a forward-facing child seat in the front seat, move the seat all the
way back.
Always transport children 12 years old and under in the back
seat and always properly use appropriate child restraints.
The passenger occupant classification sensor can automatically turn off
the passenger front air bag and side air bag (if equipped). The system is
2003 Town Car(tow)
Owners Guide (post-2002-fmt)
USA English(fus)
Seating and Safety Restraints
134

designed to help protect small (child size) occupants from air bag
deployments when they are improperly seated or restrained in the front
passenger seat contrary to proper child-seating or restraint usage
recommendations. Even with this technology, parents areSTRONGLY
encouraged to always properly restrain children in the rear seat. The
sensor also turns off the air bag(s) when the passenger seat is empty to
prevent unnecessary replacement of the air bag(s) after a collision.
Front safety belt usage sensors
The front safety belt usage sensors detect whether or not the driver and
front outboard passenger safety belts are fastened. This information
allows your Personal safety system to tailor the air bag deployment and
safety belt pretensioner activation depending upon safety belt usage.
Refer toSafety beltsection in this chapter.
Front safety belt pretensioners
The safety belt pretensioners at the front outboard seating positions are
designed to tighten the safety belts firmly against the occupant’s body
during a frontal or near-frontal collision. This maximizes the effectiveness
of the safety belts and helps properly position the occupant relative to
the air bag to improve protection. The safety belt pretensioners can be
either activated alone or, if the collision is of sufficient severity, together
with the air bags.
Front safety belt energy management retractors
The front safety belt energy management retractors allow webbing to be
pulled out of the retractor in a gradual and controlled manner in
response to the occupant’s forward momentum. This helps reduce the
risk of force-related injuries to the occupant’s chest by limiting the load
on the occupant. Refer toEnergy management featuresection in this
chapter.
Determining if the Personal safety system is operational
The Personal safety system uses a warning light in the instrument cluster
or a back-up tone to indicate the condition of the system. Refer to the
Warning lightsection in theInstrument clusterchapter. Routine
maintenance of the Personal safety system is not required.
The Restraints control module (RCM) monitors its own internal circuits
and the circuits for the air bag supplemental restraints, crash sensor(s),
safety belt pretensioners, front safety belt buckle sensors, driver seat
position sensor, and passenger occupant classification sensor. In addition,
the RCM also monitors the restraints warning light in the instrument
cluster. A difficulty with the system is indicated by one or more of the
following.
2003 Town Car(tow)
Owners Guide (post-2002-fmt)
USA English(fus)
Seating and Safety Restraints
135

How does the side air bag system work?
The design and development of the
side airbag system included
recommended testing procedures
that were developed by a group of
automotive safety experts known as
the Side Airbag Technical Working
Group. These recommended testing
procedures help reduce the risk of
injuries related to the deployment of
side airbags.
The side air bag system consists of
the following:
•An inflatable nylon bag (air bag)
with a gas generator concealed
behind the outboard bolster of
the driver and front passenger
seatbacks.
•A special seat cover designed to allow airbag deployment.
•The same warning light, electronic control and diagnostic unit as used
for the front air bags.
•Two crash sensors located near the side of the vehicle.
Side air bags, in combination with seat belts, can help reduce the risk of
severe injuries in the event of a significant side impact collision.
The side air bags are fitted on the outboard side of the seatbacks of the
front seats. In certain lateral collisions, the air bag on the side affected
by the collision will be inflated. The air bag was designed to inflate
between the door panel and occupant to further enhance the protection
provided occupants in side impact collisions.
The air bag SRS is designed to activate when the vehicle sustains lateral
deceleration sufficient to cause the sensors to close an electrical circuit
that initiates air bag inflation.
The fact that the air bags did not inflate in a collision does not mean that
something is wrong with the system. Rather, it means the forces were
not of the type sufficient to cause activation. Side air bags are designed
to inflate in side-impact collisions, not roll-over, rear-impact, frontal or
near-frontal collisions, unless the collision causes sufficient lateral
deceleration.
2003 Town Car(tow)
Owners Guide (post-2002-fmt)
USA English(fus)
Seating and Safety Restraints
153