501-20A-3
Occupant Restraints — Active
501-20A-3
DIAGNOSIS AND TESTING
Occupant Restraint System
Principles of Operation
WARNING: All safety belt assemblies,
including retractors, buckles and front
safety belt buckle support assemblies
(slider bar), if equipped, child safety seat
tether brackets and attaching hardware
should be inspected after any collision.
New safety belt assemblies should be
fitted unless a qualified technician finds
the assemblies show no damage and
operate correctly. Failure to follow these
instructions may result in personal
injury.
The safety belt system utilizes the conventional
lap and diagonal three point fixing in both front
seat positions
The front seat safety belt buckles are attached to
the seat frame of each front seat.
The front safety belt retractors incorporate a
torsion bar load limiting device. The device
consists of a retractor reel, which is mounted
onto a spindle (torsion bar), which, once the
sensor has locked the retractor reel and a
predetermined load is applied, twists and pays
out additional webbing into the system. The
torsion bar load limiting device will only react if
the safety belt is in use at the time of impact.
Emergency Locking Retractor (ELR)
The retractors in all seat positions feature ELR.
During normal operation the ELR allows free
movement of the belted occupant. In an
emergency the ELR will lock, preventing webbing
payout and hence forward movement of the
occupant. Locking may be achieved by one of
two mechanisms:
Vehicle Motion Sensor (VMS)
The ELRs VMS is operated by sudden
deceleration of the vehicle or excessive tilt. Once
operated the VMS causes a locking pawl to be
engaged, thus locking the retractor, preventing
webbing payout. The locking method used is
dependent on which type of ELR is fitted.
When the vehicle is stationary, the VMS
stabilizes, causing the pawl to disengage and
unlock the retractor, allowing webbing payout.
Webbing Motion Sensor (WMS)
The ELRs WMS is operated by rapid acceleration
of the webbing. Once operated, it causes a
locking pawl to be engaged thus locking the
retractor. Webbing payout is prevented in the
same manner as VMS.
Inspection and Verification
1. Verify the customer concern by operating the
system.
2. Visually inspect for obvious signs of
mechanical and electrical damage.
Visual Inspection Chart
Mechanical
• Loose webbing
• Damaged/frayed webbing
• Safety belt retractor and tongue assembly
• Safety belt buckle
3. If an obvious cause for an observed or
reported concern is found, correct the cause
(if possible) before proceeding to the next
stop.
4. If the concern is not visually evident, verify
the symptom and refer to the Symptom
Chart.
Symptom Chart
Condition
Possible Sources
Action
• Normal mode - occupant re-
straint system inoperative
• Broken tooth on retractor sensor
gear.
• Loose webbing.
• REFER to the Functional Test in
08/2001
2002 Bantam
