Mercedes-Benz Sprinter / Dodge Sprinter. Manual - part 239

travelling end-release seat belt buckles secured to
the inboard seat track. The driver side front seat belt
buckle of all models includes an integral seat belt
switch that detects whether its seat belt has been
fastened.

• Rear Seat Belts - All rear seating positions are

equipped with three-point seat belt systems. Each
rear seating position belt employs an integral seat
cushion frame mounted inertia latch-type retractor, a
fixed position upper seat back frame mounted turn-
ing loop, and a fixed lower seat belt anchor secured
to the seat cushion frame. All rear seat belts have
fixed end-release seat belt buckles that are also
secured to the seat cushion frame.

PASSIVE RESTRAINTS

A Next Generation driver airbag is standard facto-

ry-installed safety equipment on this model, while a
passenger side front airbag and side curtain airbags
are optional. This airbag system is a passive, inflat-
able, Supplemental Restraint System (SRS) and vehi-
cles with this equipment can be readily identified by
the “SRS - AIRBAG” logo molded into the driver air-
bag trim cover in the center of the steering wheel
and, if the vehicle is so equipped, also into the pas-
senger airbag door on the instrument panel above
the glove box (Fig. 2). Vehicles with the airbag sys-
tem can also be identified by the airbag indicator,
which will illuminate in the instrument cluster for
about six seconds as a bulb test each time the igni-
tion switch is turned to the On position. A pyrotech-
nic-type seat belt tensioner is integral to the front
seat belt retractor mounted on the lower B-pillar on
the driver side, and to the passenger side retractor of
vehicles equipped with the optional passenger side
airbag.

The supplemental restraint system includes the

following major components, which are described in
further detail elsewhere in this service information:

• Airbag Control Module - The Airbag Control

Module (ACM) is located on a mount on the floor
panel within the driver side seat riser, beneath the
driver seat in the passenger compartment.

• Airbag (SRS) Indicator - The airbag indicator

is integral to the ElectroMechanical Instrument Clus-
ter (EMIC), which is located on the instrument panel
in front of the driver.

• Clockspring - The clockspring is located near

the top of the steering column, directly beneath the
steering wheel.

• Driver Airbag - The driver airbag is located in

the center of the steering wheel, beneath the driver
airbag trim cover.

• Driver Knee Blocker - The structure of the

lower instrument panel serves as a knee blocker for
the driver.

• Passenger Airbag - The optional passenger air-

bag is located within the instrument panel, behind
the passenger airbag door on the instrument panel
above the glove box on the passenger side of the vehi-
cle.

• Passenger Knee Blocker - The structure of

the glove box door and the lower instrument panel
serve as a knee blocker for the front seat passenger.

• Seat Belt Tensioner - A seat belt tensioner is

integral to the driver side front seat belt retractor
unit, and to the passenger side front seat belt retrac-
tor unit on vehicles equipped with an optional pas-
senger airbag.

• Side Curtain Airbags - Optional side curtain

airbags are available for this model when it is also
equipped

with

dual

front

airbags.

vehicles

equipped with this option, a side curtain airbag is
located on the inside of the roof side rail within a
garnish molding that extends from the A-pillar to the
B-pillar above each front door opening within the
passenger compartment of the vehicle.

• Side Impact Sensor - Two side impact sensors

are used on vehicles equipped with the optional side
curtain airbags, one on each side of the vehicle. One
sensor is located near the front of each front door
step well, concealed behind the step well trim.

The ACM contains a central processing unit and

programming that allows it to communicate on a
serial data bus diagnostic circuit connected to the
16-way Data Link Connector (DLC) located below the
left end of the instrument panel. This method of com-
munication is used for initialization of the ACM and
for diagnosis of the SRS circuits and components
using a diagnostic scan tool.

Hard wired circuitry connects the supplemental

restraint system components to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system,

Fig. 2 SRS Logo

RESTRAINTS

8O - 3

and to the supplemental restraint system compo-
nents through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.

OPERATION

ACTIVE RESTRAINTS

The primary passenger restraints in this or any

other vehicle are the standard equipment factory-in-
stalled seat belts. Seat belts are referred to as an
active restraint because the vehicle occupants are
required to physically fasten and properly adjust
these restraints in order to benefit from them. See
the owner’s manual in the vehicle glove box for more
information on the features, use and operation of all
of the factory-installed active restraints.

PASSIVE RESTRAINTS

The passive restraints are referred to as a supple-

mental restraint system because they were designed
and are intended to enhance the protection for the
occupants of the vehicle only when used in conjunc-
tion with the seat belts. They are referred to as pas-
sive restraints because the vehicle occupants are not
required to do anything to make them operate; how-
ever, the vehicle occupants must be wearing their
seat belts in order to obtain the maximum safety
benefit

from

the

factory-installed

supplemental

restraint system.

The supplemental restraint system electrical cir-

cuits are continuously monitored and controlled by a
microprocessor and software contained within the
Airbag Control Module (ACM). An airbag indicator in
the ElectroMechanical Instrument Cluster (EMIC)
illuminates for about four seconds as a bulb test each
time the ignition switch is turned to the On or Start
positions. Following the bulb test, the airbag indica-
tor is turned on or off by the ACM to indicate the
status of the supplemental restraint system. If the
airbag indicator comes on either solid or flashing at
any time other than during the bulb test, it indicates
that there is a problem in the supplemental restraint
system electrical circuits. Such a problem may cause
airbags not to deploy when required, or to deploy
when not required.

Deployment

the

supplemental

restraints

depends upon the angle and severity of an impact.
Deployment is not based upon vehicle speed; rather,
deployment is based upon the rate of deceleration as
measured by the forces of gravity (G force) upon the
impact sensor(s). When an impact is severe enough,

the microprocessor in the ACM signals the inflator of
the appropriate airbag units to deploy their airbag
cushions. The front seat belt tensioners are provided
with a deployment signal by the ACM in conjunction
with the driver and passenger airbags.

During a frontal vehicle impact, the knee blockers

work in concert with properly fastened and adjusted
seat belts to restrain both the driver and the front
seat passenger in the proper position for an airbag
deployment. The knee blockers also absorb and dis-
tribute the crash energy from the driver and the
front seat passenger to the structure of the instru-
ment panel. The seat belt tensioners remove the
slack from the front seat belts to provide further
assurance that the driver and front seat passenger
are properly positioned and restrained for an airbag
deployment.

Typically, the vehicle occupants recall more about

the events preceding and following a collision than
they do of an airbag deployment itself. This is
because the airbag deployment and deflation occur so
rapidly. In a typical 48 kilometer-per-hour (30 mile-
per-hour) barrier impact, from the moment of impact
until the airbags are fully inflated takes only a few
milliseconds. Within one to two seconds from the
moment of impact, the airbags are almost entirely
deflated. The times cited for these events are approx-
imations, which apply only to a barrier impact at the
given speed. Actual times will vary somewhat,
depending upon the vehicle speed, impact angle,
severity of the impact, and the type of collision.

When the ACM monitors a problem in any of the

airbag system circuits or components, including the
seat belt tensioners, it stores a fault code or Diagnos-
tic Trouble Code (DTC) in its memory circuit and
sends a hard wired output to the EMIC to turn on
the airbag indicator. If the EMIC detects a problem
in the airbag indicator or airbag indicator circuit, the
cluster will flash the seatbelt indicator on and off.
Proper testing of the supplemental restraint system
components as well as the retrieval or erasure of a
DTC from the ACM requires the use of a diagnostic
scan tool. Refer to the appropriate diagnostic infor-
mation.

See the owner’s manual in the vehicle glove box for

more information on the features, use and operation
of all of the factory-installed passive restraints.

8O - 4

RESTRAINTS

WARNINGS - RESTRAINT SYSTEM

WARNING: To avoid personal injury or death, during
and

following

any

seat

belt

service,

carefully

inspect all seat belts, buckles, mounting hardware,
retractors, tether straps, and anchors for proper
installation, operation, or damage. Replace any belt
that is cut, frayed, or torn. Straighten any belt that
is twisted. Tighten any loose fasteners. Replace any
belt that has a damaged or inoperative buckle or
retractor. Replace any belt that has a bent or dam-
aged latch plate or anchor plate. Never attempt to
repair a seat belt component. Always replace dam-
aged or faulty seat belt components with the cor-
rect, new and unused replacement parts listed in
the DaimlerChrysler Mopar Parts Catalog.

WARNING: To avoid personal injury or death, on
vehicles equipped with airbags, disable the supple-
mental

restraint

system

before

attempting

any

steering wheel, steering column, airbag, seat belt
tensioner, impact sensor, or instrument panel com-
ponent diagnosis or service. Disconnect and isolate
the battery negative (ground) cable, then wait two
minutes for the system capacitor to discharge
before performing further diagnosis or service. This
is the only sure way to disable the supplemental
restraint system. Failure to take the proper precau-
tions could result in accidental airbag deployment.

WARNING: To avoid personal injury or death on
vehicles equipped with airbags, before performing
any welding operations disconnect and isolate the
battery negative (ground) cable and disconnect all
wire harness connectors from the Airbag Control
Module (ACM). Failure to take the proper precau-
tions could result in accidental airbag deployment
and other possible damage to the supplemental
restraint system circuits and components.

WARNING: To avoid personal injury or death, do not
attempt to dismantle an airbag unit or tamper with
its inflator. Do not puncture, incinerate, or bring
into contact with electricity. Do not store at temper-
atures exceeding 93° C (200° F). An airbag inflator
unit may contain sodium azide and potassium
nitrate.

These

materials

are

poisonous

and

extremely flammable. Contact with acid, water, or
heavy metals may produce harmful and irritating
gases (sodium hydroxide is formed in the presence
of moisture) or combustible compounds. An airbag
inflator unit may also contain a gas canister pres-
surized to over 2500 psi.

WARNING: To avoid personal injury or death, when
handling a seat belt tensioner retractor, proper care
should be exercised to keep fingers out from under
the retractor cover and away from the seat belt
webbing where it exits from the retractor cover.

WARNING: To avoid personal injury or death,
replace all restraint system components only with
parts specified in the DaimlerChrysler Mopar Parts
Catalog. Substitute parts may appear interchange-
able, but internal differences may result in inferior
occupant protection.

WARNING: To avoid personal injury or death, the
fasteners, screws, and bolts originally used for the
restraint

system

components

must

never

replaced with any substitutes. These fasteners have
special coatings and are specifically designed for
the restraint system. Any time a new fastener is
needed, replace it with the correct fasteners pro-
vided in the service package or specified in the
DaimlerChrysler Mopar Parts Catalog.

WARNING: To avoid personal injury or death, when
a steering column has an airbag unit attached,
never place the column on the floor or any other
surface with the steering wheel or airbag unit face
down.

DIAGNOSIS AND TESTING - SUPPLEMENTAL
RESTRAINT SYSTEM

Proper diagnosis and testing of the supplemental

restraint system components or the Airbag Control
Module (ACM), initialization of the ACM, as well as
the retrieval or erasure of a Diagnostic Trouble Code
(DTC) from the ACM requires the use of a DRBIII

scan tool. Refer to the appropriate diagnostic infor-
mation.

WARNING: To avoid personal injury or death, on
vehicles equipped with airbags, disable the supple-
mental

restraint

system

before

attempting

any

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8O - 5

STANDARD PROCEDURE

STANDARD PROCEDURE - HANDLING NON -
DEPLOYED SUPPLEMENTAL RESTRAINTS

At no time should any source of electricity be per-

mitted near the inflator on the back of a non-de-
ployed airbag or seat belt tensioner. When carrying a
non-deployed airbag, the trim cover or airbag cushion
side of the unit should be pointed away from the
body to minimize injury in the event of an accidental
deployment. If the airbag unit is placed on a bench or
any other surface, the trim cover or airbag cushion
side of the unit should be face up to minimize move-
ment in the event of an accidental deployment. When
handling a non-deployed seat belt tensioner, take
proper care to keep fingers out from under the
retractor cover and away from the seat belt webbing
where it exits from the retractor cover. In addition,
the supplemental restraint system should be dis-
armed whenever any steering wheel, steering col-
umn, seat belt tensioner, airbag, impact sensor, or
instrument panel components require diagnosis or
service. Failure to observe this warning could result
in

accidental

deployment

and

possible

personal

injury.

All damaged, faulty or non-deployed airbags and

seat belt tensioners which are replaced on vehicles
are to be handled and disposed of properly. If an air-
bag or seat belt tensioner unit is faulty or damaged
and non-deployed, refer to the Hazardous Substance
Control System for proper disposal. Dispose of all
non-deployed and deployed airbags and seat belt ten-
sioners in a manner consistent with state, provincial,
local and federal regulations.

SUPPLEMENTAL RESTRAINT STORAGE

Airbags and seat belt tensioners must be stored in

their original, special container until they are used
for service. Also, they must be stored in a clean, dry
environment; away from sources of extreme heat,
sparks, and high electrical energy. Always place or
store any airbag on a surface with its trim cover or
airbag cushion side facing up, to minimize movement
in case of an accidental deployment.

STANDARD PROCEDURE - SERVICE AFTER A
SUPPLEMENTAL RESTRAINT DEPLOYMENT

Any vehicle which is to be returned to use follow-

ing a supplemental restraint deployment, must have
the deployed restraints replaced. In addition, if the
driver airbag has been deployed, the clockspring and
the steering wheel must be replaced. If the passenger
airbag has been deployed, the instrument panel must
be replaced. The seat belt tensioners are deployed by
the same signal that deploys the driver and passen-
ger airbags and must also be replaced if either front
airbag has been deployed. These components are not

intended for reuse and will be damaged or weakened
as a result of a supplemental restraint deployment,
which may or may not be obvious during a visual
inspection.

It is also critical that the mounting surfaces and/or

mounting brackets for the Airbag Control Module
(ACM) and the side impact sensors be closely
inspected and restored to their original conditions fol-
lowing any vehicle impact damage. Because the ACM
and each impact sensor are used by the supplemental
restraint system to monitor or confirm the direction
and severity of a vehicle impact, improper orientation
or insecure fastening of these components may cause
airbags not to deploy when required, or to deploy
when not required.

All other vehicle components should be closely

inspected

following

any

supplemental

restraint

deployment, but are to be replaced only as required
by the extent of the visible damage incurred.

CLEANUP PROCEDURE

Following a supplemental restraint deployment,

the vehicle interior will contain a powdery residue.
This residue consists primarily of harmless particu-
late by-products of the small pyrotechnic charge that
initiates the propellant used to deploy a supplemen-
tal restraint. However, this residue may also contain
traces of sodium hydroxide powder, a chemical
by-product of the propellant material that is used to
generate the inert gas that inflates the airbag. Since
sodium hydroxide powder can irritate the skin, eyes,
nose, or throat, be certain to wear safety glasses,
rubber

gloves,

and

long-sleeved

shirt

during

cleanup (Fig. 3).

WARNING: To avoid personal injury or death, if you
experience skin irritation during cleanup, run cool
water over the affected area. Also, if you experience
irritation of the nose or throat, exit the vehicle for
fresh air until the irritation ceases. If irritation con-
tinues, see a physician.

Fig. 3 Wear Safety Glasses and Rubber Gloves -

Typical

8O - 6

RESTRAINTS

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