Mercedes-Benz Sprinter / Dodge Sprinter. Manual - part 240

(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 or
damaged 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 diagnostic scan tool to verify proper supplemental
restraint system operation following the service or
replacement of any supplemental restraint system
component.

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

restraint

system

before

attempting

any

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.

(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 diagnostic scan tool con-

tains the latest version of the proper diagnostic soft-
ware. Connect the diagnostic to the 16-way Data
Link Connector (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 diagnostic scan tool.

(4) Check to be certain that nobody is in the vehi-

cle, then reconnect the battery negative cable.

(5) Using the diagnostic, read and record the

active (current) Diagnostic Trouble Code (DTC) data.

(6) Next, use the diagnostic to 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 diagnostic to erase the stored DTC

data. If any problems remain, the stored DTC data
will not erase. Refer to the appropriate diagnostic
information 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, and
then go out. This indicates that the supplemental

Fig. 4 Vacuum Heater and A/C Outlets - Typical

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

RESTRAINTS

8O - 7

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
supplemental 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 diagnostic scan 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 the
vehicle (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 aluminum ACM housing is the electronic cir-
cuitry of the ACM which includes a microprocessor,
an electronic impact sensor, an electronic safing sen-
sor, and an energy storage capacitor. A stamped
metal cover plate is permanently secured to the bot-
tom 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.
The ACM housing has integral mounting flanges on
three corners. 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 are cali-

brated for the specific vehicle, and are only serviced
as a unit with the ACM. In addition, the ACM must
be electronically programmed for the correct stan-
dard and optional supplemental restraint system
components installed in the vehicle. 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 a diagnostic scan tool using a diagnostic Serial

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

RESTRAINTS

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 for
the 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-storage capaci-

tor. When the ignition switch is in the On position,
this capacitor is continually being charged with
enough electrical energy to deploy the supplemental
restraint components for up to one second following 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.

Two sensors are contained within the ACM, an

electronic impact sensor and a safing sensor. These
electronic sensors are accelerometers that sense the
rate of vehicle deceleration, which provide verifica-
tion of the direction and severity of an impact. On

models equipped with optional side curtain airbags,
the ACM also monitors inputs from two remote side
impact sensors located within the left and right front
door step wells to control deployment of the side cur-
tain airbag units.

The safing sensor is an electronic accelerometer

sensor within the ACM that provides an additional
logic input to the ACM microprocessor. The safing
sensor is used to verify the need for a supplemental
restraint deployment by detecting impact energy of a
lesser magnitude than that of the primary electronic
impact sensors, and must exceed a safing threshold
in order for the airbags to deploy. Vehicles equipped
with optional side curtain airbags feature a second
safing sensor within the ACM to provide confirma-
tion to the ACM microprocessor of side impact forces.
This second safing sensor is a bi-directional unit that
detects impact forces from either side of the vehicle.

Pre-programmed decision algorithms in the ACM

microprocessor determine when the deceleration rate
as signaled by the impact sensors and the safing sen-
sors indicate 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 front
airbags and seat belt tensioners and, if the vehicle is
so equipped, either side curtain airbag unit.

The ACM also provides a hard wired electrical

crash

signal

output

following

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 diagnostic scan tool. Refer
to the appropriate diagnostic information. The hard
wired inputs and outputs for the ACM may be diag-
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 diagnostic scan tool. Refer to
the appropriate diagnostic information.

RESTRAINTS

8O - 9

REMOVAL

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, never
strike or drop the airbag control module as it can
damage the impact sensor or affect its calibration.
The airbag control module contains the impact sen-
sor, which enables the system to deploy the supple-
mental restraints. 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 acci-
dental,

incomplete,

improper

supplemental

restraint deployment.

(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).

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

RESTRAINTS

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