MERCEDES-BENZ SPRINTER 2005 Service Repair Manual

ACTIVE RESTRAINTS
The active restraints for this model include:
²Front Seat Belts- Both outboard front seating
positions are equipped with three-point seat belt sys-
tems employing a lower B-pillar mounted inertia
latch-type retractors, height-adjustable upper B-pil-
lar mounted turning loops, travelling lower seat belt
anchors secured to the outboard seat tracks, and
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.
²Rear 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 is optional. This airbag
system is a passive, inflatable, Supplemental
Restraint System (SRS) and vehicles with this equip-
ment can be readily identified by the ªSRS - AIR-
BAGº logo molded into the driver airbag trim cover
in the center of the steering wheel and, if the vehicle
is so equipped, also into the passenger airbag door on
the instrument panel above the glove box (Fig. 2).
Vehicles with the airbag system 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 ignition switch is turned to the On
position. A pyrotechnic-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 pas-
senger 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:
²Airbag 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.
²Airbag (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.²Clockspring- The clockspring is located near
the top of the steering column, directly beneath the
steering wheel.
²Driver Airbag- The driver airbag is located in
the center of the steering wheel, beneath the driver
airbag trim cover.
²Driver Knee Blocker- The structure of the
lower instrument panel serves as a knee blocker for
the driver.
²Passenger 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.
²Passenger Knee Blocker- The structure of
the glove box door and the lower instrument panel
serve as a knee blocker for the front seat passenger.
²Seat 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.
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 DRBIIItscan 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,
and to the supplemental restraint system compo-
nents through the use of a combination of soldered
Fig. 2 SRS Logo
VARESTRAINTS 8O - 3
RESTRAINTS (Continued)

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 vehicleonlywhen 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 of 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. When an impact is severe enough, the
microprocessor in the ACM signals the inflator of the
appropriate airbag units to deploy their airbag cush-
ions. 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 distribute the crash
energy from the driver and the front seat passenger
to the structure of the instrument 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
front airbag system circuits or components, including
the seat belt tensioners, it stores a fault code or
Diagnostic 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 prob-
lem in the airbag indicator or airbag indicator circuit,
the cluster will flash the seatbelt indicator on and
off. Proper testing of the supplemental restraint sys-
tem components as well as the retrieval or erasure of
a DTC from the ACM requires the use of a DRBIIIt
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 RESTRAINTSVA
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WARNING
WARNINGS - RESTRAINT SYSTEM
WARNING: 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 DAMAGED
LATCH PLATE OR ANCHOR PLATE. NEVER
ATTEMPT TO REPAIR A SEAT BELT COMPONENT.
ALWAYS REPLACE DAMAGED OR FAULTY SEAT
BELT COMPONENTS WITH THE CORRECT, NEW
AND UNUSED REPLACEMENT PARTS LISTED IN
THE DAIMLERCHRYSLER MOPAR PARTS CATA-
LOG.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY 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 PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, BEFORE PERFORMING ANY WELDING
OPERATIONS DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE (GROUND) CABLE AND DIS-
CONNECT ALL WIRE HARNESS CONNECTORS
FROM THE AIRBAG CONTROL MODULE (ACM).
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT AND OTHER POSSIBLE DAMAGE TO THE
SUPPLEMENTAL RESTRAINT SYSTEM CIRCUITS
AND COMPONENTS.
WARNING: AN AIRBAG INFLATOR UNIT MAY CON-
TAIN SODIUM AZIDE AND POTASSIUM NITRATE.THESE MATERIALS ARE POISONOUS AND
EXTREMELY FLAMMABLE. CONTACT WITH ACID,
WATER, OR HEAVY METALS MAY PRODUCE HARM-
FUL AND IRRITATING GASES (SODIUM HYDROXIDE
IS FORMED IN THE PRESENCE OF MOISTURE) OR
COMBUSTIBLE COMPOUNDS. AN AIRBAG INFLA-
TOR UNIT MAY ALSO CONTAIN A GAS CANISTER
PRESSURIZED TO OVER 2500 PSI. 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 TEMPERATURES
EXCEEDING 93É C (200É F).
WARNING: WHEN HANDLING A SEAT BELT TEN-
SIONER 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: REPLACE ALL RESTRAINT SYSTEM
COMPONENTS ONLY WITH PARTS SPECIFIED IN
THE DAIMLERCHRYSLER MOPAR PARTS CATA-
LOG. SUBSTITUTE PARTS MAY APPEAR INTER-
CHANGEABLE, BUT INTERNAL DIFFERENCES MAY
RESULT IN INFERIOR OCCUPANT PROTECTION.
WARNING: THE FASTENERS, SCREWS, AND
BOLTS ORIGINALLY USED FOR THE RESTRAINT
SYSTEM COMPONENTS HAVE SPECIAL COATINGS
AND ARE SPECIFICALLY DESIGNED FOR THE
RESTRAINT SYSTEM. THEY MUST NEVER BE
REPLACED WITH ANY SUBSTITUTES. ANY TIME A
NEW FASTENER IS NEEDED, REPLACE IT WITH
THE CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
DAIMLERCHRYSLER MOPAR PARTS CATALOG.
WARNING: WHEN A STEERING COLUMN HAS AN
AIRBAG UNIT ATTACHED, NEVER PLACE THE COL-
UMN 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 DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
VARESTRAINTS 8O - 5
RESTRAINTS (Continued)

WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY 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 PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
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, driver airbag, passenger
airbag, or instrument panel components require diag-
nosis 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. The seat belt
tensioners are deployed by the same signal that
deploys the driver and passenger airbags and must
also be replaced if either airbag has been deployed.
These components are not intended for reuse and
will be damaged or weakened as a result of a supple-
mental 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) be closely inspected and restored to their orig-
inal conditions following any vehicle impact damage.
Because the ACM contains the impact sensor that is
used by the supplemental restraint system to moni-
tor or confirm the direction and severity of a vehicle
impact, improper orientation or insecure fastening of
this component 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 a long-sleeved shirt during
cleanup (Fig. 3).
8O - 6 RESTRAINTSVA
RESTRAINTS (Continued)

WARNING: 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 CONTINUES, SEE A PHYSI-
CIAN.
(1) Begin the cleanup by using a vacuum cleaner
to remove any residual powder from the vehicle inte-
rior. Clean from outside the vehicle and work your
way inside, so that you avoid kneeling or sitting on a
non-cleaned area.
(2) Be certain to vacuum the heater and air condi-
tioning outlets as well (Fig. 4). Run the heater and
air conditioner blower on the lowest speed setting
and vacuum any powder expelled from the outlets.
CAUTION: All damaged, faulty, or non-deployed
supplemental restraints which are replaced on vehi-
cles are to be handled and disposed of properly. If
an airbag unit or seat belt tensioner unit is faulty ordamaged and non-deployed, refer to the Hazardous
Substance Control System for proper disposal. Be
certain to dispose of all non-deployed and deployed
supplemental restraints in a manner consistent with
state, provincial, local and federal regulations.
(3) Next, remove the deployed supplemental
restraints from the vehicle. Refer to the appropriate
service removal procedures.
(4) You may need to vacuum the interior of the
vehicle a second time to recover all of the powder.
STANDARD PROCEDURE - VERIFICATION TEST
The following procedure should be performed using
a DRBIIItscan tool to verify proper supplemental
restraint system operation following the service or
replacement of any supplemental restraint system
component.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY 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 PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) During the following test, the battery negative
cable remains disconnected and isolated, as it was
during the supplemental restraint system component
removal and installation procedures.
(2) Be certain that the DRBIIItscan tool contains
the latest version of the proper DRBIIItsoftware.
Connect the DRBIIItto the 16-way Data Link Con-
nector (DLC). The DLC is located on the dash panel
beneath the driver side lower edge of the instrument
panel, outboard of the steering column (Fig. 5).
(3) Turn the ignition switch to the On position and
exit the vehicle with the DRBIIItscan tool.
(4) Check to be certain that nobody is in the vehi-
cle, then reconnect the battery negative cable.
(5) Using the DRBIIIt, read and record the active
(current) Diagnostic Trouble Code (DTC) data.
(6) Next, use the DRBIIItto read and record any
stored (historical) DTC data.
(7) If any DTC is found in Step 5 or Step 6, refer
to the appropriate diagnostic information.
(8) Use the DRBIIItto erase the stored DTC data.
If any problems remain, the stored DTC data will not
Fig. 3 Wear Safety Glasses and Rubber Gloves -
Typical
Fig. 4 Vacuum Heater and A/C Outlets - Typical
VARESTRAINTS 8O - 7
RESTRAINTS (Continued)

erase. Refer to the appropriate diagnostic informa-
tion to diagnose any stored DTC that will not erase.
If the stored DTC information is successfully erased,
go to Step 9.
(9) Turn the ignition switch to the Off position for
about fifteen seconds, and then back to the On posi-
tion. Observe the airbag indicator in the instrument
cluster. It should illuminate for four seconds, then go
out. This indicates that the supplemental restraint
system is functioning normally and that the repairs
are complete. If the airbag indicator fails to light, or
lights and stays on, there is still an active supple-
mental restraint system fault or malfunction. Refer
to the appropriate diagnostic information to diagnose
the problem.
NOTE: If the Airbag Control Module (ACM) has been
replaced with a new unit, it will be necessary to ini-
tialize the new ACM. In order to function properly,
the ACM must be programmed for the correct stan-
dard and optional supplemental restraint system
components installed in the vehicle. To initialize the
ACM, a DRBIIITscan tool is required. Refer to the
appropriate diagnostic information.
AIRBAG CONTROL MODULE
DESCRIPTION
The Airbag Control Module (ACM) is secured with
three screws to the top mounting surface of a
stamped steel bracket that is welded onto the floor
panel within the seat riser underneath the driver
side front seat in the passenger compartment of thevehicle (Fig. 6). A molded plastic protective cover is
installed over the ACM and secured with integral
snap features to a flat metal base plate sandwiched
between the bottom of the ACM and the mounting
bracket on the floor panel (Fig. 7). This cover is
designed to shield the ACM and its wire harness con-
nection from other electrical components and wiring
located within the seat riser area beneath the driver
seat, and must always be reinstalled following ser-
vice removal.
Concealed within a hollow in the center of the die
cast white metal ACM housing is the electronic cir-
cuitry of the ACM which includes a microprocessor,
Fig. 5 16-Way Data Link Connector
1 - BOTTOM OF INSTRUMENT PANEL
2 - CONNECTOR COVER
3 - 16-WAY DATA LINK CONNECTOR
4 - DASH PANEL
5 - INSIDE HOOD RELEASE LEVER
Fig. 6 Airbag Control Module
1 - AIRBAG CONTROL MODULE
2 - LABEL
3 - ORIENTATION ARROW
4 - CONNECTOR RECEPTACLE
Fig. 7 ACM Bracket
1 - ACM BRACKET
2 - SEAT RISER
3 - EYELET TERMINAL
4 - ACM CONNECTOR
5 - FLOOR PANEL
8O - 8 RESTRAINTSVA
RESTRAINTS (Continued)

an electronic impact sensor, and an energy storage
capacitor. The ACM housing has three integral
mounting tabs. A stamped metal cover plate is per-
manently secured to the bottom of the ACM housing
to enclose and protect the internal electronic circuitry
and components. An arrow printed on a label on the
top of the ACM housing near the rear provides a
visual verification of the proper orientation of the
unit, and should always be pointed toward the front
of the vehicle. A molded plastic electrical connector
receptacle containing numerous terminal pins is inte-
gral to the left facing side of the ACM housing. These
terminal pins connect the ACM to the vehicle electri-
cal system through a dedicated take out and connec-
tor of the vehicle wire harness.
The impact sensor internal to the ACM is cali-
brated for the specific vehicle, and is only serviced as
a unit with the ACM. The ACM cannot be repaired or
adjusted and, if damaged or faulty, it must be
replaced.
OPERATION
The microprocessor in the Airbag Control Module
(ACM) contains the supplemental restraint system
logic circuits and controls all of the supplemental
restraint system components. The ACM uses
On-Board Diagnostics (OBD) and can communicate
with the DRBIIItscan tool using a diagnostic Serial
Communication Interface (SCI) data bus line for sup-
plemental restraint system programming or diagno-
sis and testing through the 16-way Data Link
Connector (DLC) located on the dash panel below the
driver side end of the instrument panel. A hard wired
output from the ACM is used for control of the airbag
indicator in the ElectroMechanical Instrument Clus-
ter (EMIC). (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER/AIRBAG INDICATOR -
OPERATION).
The ACM microprocessor continuously monitors all
of the supplemental restraint system electrical cir-
cuits to determine the system readiness. If the ACM
detects a monitored system fault, it sets an appropri-
ate Diagnostic Trouble Code (DTC) and sends an out-
put to the EMIC to turn on the airbag indicator. The
ACM illuminates the indicator for about four seconds
each time the ignition switch is turned to the On
position as a bulb test. If the indicator remains illu-
minated for about ten seconds after the ignition
switch is turned to the On position, the ACM has
detected a non-critical fault that poses no danger to
the vehicle occupants. If the airbag indicator illumi-
nates solid (not flashing) while driving or stays on
longer than ten seconds following the bulb test, the
ACM has detected a critical fault that may cause the
airbags not to deploy when required or to deploy
when not required. An active fault only remains forthe duration of the fault, or in some cases, for the
duration of the current ignition switch cycle, while a
stored fault causes a DTC to be stored in memory by
the ACM.
The ACM receives battery current through a fused
ignition switch output circuit. The ACM receives
ground through a ground circuit and take out of the
vehicle wire harness. This take out has an eyelet ter-
minal connector secured by a nut to a ground stud on
the floor panel directly below the ACM within the
driver side seat riser. A case ground is also provided
for the ACM through a ground circuit and eyelet ter-
minal connector secured under the left rear ACM
mounting screw. These connections allow the ACM to
be operational whenever the ignition switch is in the
On position. The ACM also contains an energy-stor-
age capacitor. When the ignition switch is in the On
position, this capacitor is continually being charged
with enough electrical energy to deploy the supple-
mental restraint components for up to one second fol-
lowing a battery disconnect or failure. The purpose of
the capacitor is to provide backup supplemental
restraint system protection in case there is a loss of
battery current supply to the ACM during an impact.
An electronic impact sensor is contained within the
ACM. The electronic impact sensor is an accelerome-
ter that senses the rate of vehicle deceleration, which
provides verification of the direction and severity of
an impact. A pre-programmed decision algorithm in
the ACM microprocessor determines when the decel-
eration rate as signaled by the impact sensor indi-
cates an impact that is severe enough to require
supplemental restraint system protection. When the
programmed conditions are met, the ACM sends the
proper electrical signals to deploy the seat belt ten-
sioners and front airbags.
The ACM also provides a hard wired electrical
crash signal output following a supplemental
restraint deployment event. This output is used to
signal other electronic modules in the vehicle to pro-
vide their enhanced accident response features,
which include automatically disabling the engine
from running and unlocking all of the doors. How-
ever, these responses are each dependent upon the
circuits, components, and modules controlling these
features remaining intact from collateral damage
incurred during the vehicle impact.
A single ACM is used for all variations of the sup-
plemental restraint system available in this vehicle.
This ACM is programmable and in order to function
properly it must be programmed for the correct vehi-
cle supplemental restraint system equipment using
an initialization procedure. The initialization proce-
dure requires the use of a DRBIIItscan tool. Refer to
the appropriate diagnostic information. The hard
wired inputs and outputs for the ACM may be diag-
VARESTRAINTS 8O - 9
AIRBAG CONTROL MODULE (Continued)

nosed and tested using conventional diagnostic tools
and procedures. However, conventional diagnostic
methods will not prove conclusive in the diagnosis of
the ACM or the supplemental restraint system. The
most reliable, efficient, and accurate means to diag-
nose the ACM or the supplemental restraint system
requires the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY 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 PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
WARNING: THE AIRBAG CONTROL MODULE CON-
TAINS THE IMPACT SENSOR, WHICH ENABLES
THE SYSTEM TO DEPLOY THE SUPPLEMENTAL
RESTRAINTS. NEVER STRIKE OR DROP THE AIR-
BAG CONTROL MODULE, AS IT CAN DAMAGE THE
IMPACT SENSOR OR AFFECT ITS CALIBRATION. IF
AN AIRBAG CONTROL MODULE IS ACCIDENTALLY
DROPPED DURING SERVICE, THE MODULE MUST
BE SCRAPPED AND REPLACED WITH A NEW UNIT.
FAILURE TO OBSERVE THIS WARNING COULD
RESULT IN ACCIDENTAL, INCOMPLETE, OR
IMPROPER SUPPLEMENTAL RESTRAINT DEPLOY-
MENT AND POSSIBLE OCCUPANT INJURIES.
(1) Disconnect and isolate the battery negative
cable. Wait two minutes for the system capacitor to
discharge before further service.
(2) Move the driver side front seat to its most for-
ward position for easiest access to the seat riser
cover panel (Fig. 8).
(3) Remove the two screws that secure the cover
panel to the top of the seat riser under the driver
side front seat (Fig. 9).
(4) Remove the cover panel from the top of the
driver side seat riser.
(5) Remove the two screws that secure the control
module bracket to the top of the seat riser under the
driver side front seat (Fig. 10).(6) Remove the control module bracket from the
top of the driver side seat riser.
(7) Locate the Airbag Control Module (ACM) in the
right rear corner of the area within the driver side
seat riser. Firmly grasp and pull upward on the
molded plastic cover to unsnap it from over the ACM
(Fig. 11).
Fig. 8 Airbag Control Module Location
1 - DRIVER SEAT
2 - AIRBAG CONTROL MODULE
3 - SEAT RISER
Fig. 9 Seat Riser Cover
1 - DRIVER SEAT BACK
2 - COVER PANEL
3 - SCREW (2)
4 - SEAT RISER
8O - 10 RESTRAINTSVA
AIRBAG CONTROL MODULE (Continued)

(8) Remove the three screws that secure the ACM
to the bracket that is welded onto the floor panel
under the driver side front seat (Fig. 12).
(9) Lift the ACM upward far enough to access the
ACM wiring connection. Depress the release and lift
the lever arm to disconnect the vehicle wire harness
connector for the ACM from the ACM connector
receptacle located on the left facing side of the mod-
ule.
(10) Remove the ACM from within the driver side
front seat riser.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BAT-
TERY 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 PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
WARNING: THE AIRBAG CONTROL MODULE CON-
TAINS THE IMPACT SENSOR, WHICH ENABLES
THE SYSTEM TO DEPLOY THE SUPPLEMENTAL
RESTRAINTS. NEVER STRIKE OR DROP THE AIR-
BAG CONTROL MODULE, AS IT CAN DAMAGE THE
IMPACT SENSOR OR AFFECT ITS CALIBRATION. IF
AN AIRBAG CONTROL MODULE IS ACCIDENTALLY
DROPPED DURING SERVICE, THE MODULE MUST
BE SCRAPPED AND REPLACED WITH A NEW UNIT.
FAILURE TO OBSERVE THIS WARNING COULD
RESULT IN ACCIDENTAL, INCOMPLETE, OR
IMPROPER SUPPLEMENTAL RESTRAINT DEPLOY-
MENT AND POSSIBLE OCCUPANT INJURIES.
Fig. 10 Control Module Bracket
1 - SEAT RISER
2 - SCREW (2)
3 - CONTROL MODULE BRACKET
Fig. 11 ACM Cover
1 - SEAT RISER
2 - COVER
3 - ACM
Fig. 12 Airbag Control Module Remove/Install
1 - ACM LABEL
2 - ACM
3 - SCREW (3)
4 - GROUND EYELET
5 - CONNECTOR
VARESTRAINTS 8O - 11
AIRBAG CONTROL MODULE (Continued)

(1) Reconnect and latch the vehicle wire harness
connector for the ACM to the ACM connector recep-
tacle located on the left facing side of the module
(Fig. 12).
(2) Carefully position the ACM cover base plate
onto the mounting bracket that is welded onto the
floor panel under the driver side front seat (Fig. 13).
(3) Carefully position the ACM onto the ACM cover
base plate. When the ACM is correctly positioned, the
three ACM mounting tabs will be aligned with the
holes in the cover base plate and the mounting
bracket, and the orientation arrow on the ACM label
will be pointed forward in the vehicle.
(4) Install and tighten the three screws that secure
the ACM to the mounting bracket that is welded onto
the floor panel within the driver side front seat riser.
Be certain that the ground eyelet terminal is
installed under the screw for the left rear mounting
tab. Tighten the screws to 12 N´m (105 in. lbs.).
(5) Position the ACM cover over the ACM and
press it down firmly and evenly until it snaps into
position over the ACM cover base plate (Fig. 11).
(6) Position the control module bracket onto the
top of the driver side seat riser (Fig. 10).
(7) Install and tighten the two screws that secure
the control module bracket to the top of the seat riser
under the driver side front seat. Tighten the screws
to 2 N´m (18 in. lbs.).
(8) Position the cover panel onto the top of the
driver side seat riser (Fig. 9).
(9) Install and tighten the two screws that secure
the cover panel to the top of the seat riser under the
driver side front seat. Tighten the screws to 2 N´m
(18 in. lbs.).(10) Move the driver side front seat back to its
driving position.
(11) Do not reconnect the battery negative cable at
this time. The supplemental restraint system verifi-
cation test procedure should be performed following
service of any supplemental restraint system compo-
nent. (Refer to 8 - ELECTRICAL/RESTRAINTS -
STANDARD PROCEDURE - VERIFICATION TEST).
NOTE: If the Airbag Control Module (ACM) has been
replaced with a new unit, it will be necessary to ini-
tialize the new ACM. In order to function properly,
the ACM must be programmed for the correct stan-
dard and optional supplemental restraint system
components installed in the vehicle. To initialize the
ACM, a DRBIIITscan tool is required. Refer to the
appropriate diagnostic information.
CLOCKSPRING
DESCRIPTION
The clockspring assembly is secured with two
screws onto the multi-function switch housing near
the top of the steering column directly below the
steering wheel (Fig. 14). The clockspring consists of a
flat, round molded plastic case that contains a spool-
like molded plastic rotor with a large exposed hub
covering the entire upper surface of the case. The
rotor hub has a large center hole that is internally
ribbed to engage splines on the upper steering col-
umn shaft, and two small clearance holes that pro-
Fig. 13 ACM Cover Base Plate
1 - BASE PLATE
2 - SEAT RISER
3 - GROUND EYELET TERMINAL
4 - ACM CONNECTOR
5 - FLOOR PANEL
Fig. 14 Clockspring
1 - PIGTAIL WIRE CONNECTOR (2)
2 - CASE
3 - CANCEL CAM
4 - ROTOR
5 - SCREW (2)
6 - HORN SWITCH CONNECTOR (2)
7 - AIRBAG CONNECTOR
8O - 12 RESTRAINTSVA
AIRBAG CONTROL MODULE (Continued)