Dodge dakota 2002, Service Manual

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On models equipped with optional side curtain air-
bags, the ACM communicates with both the left and
right Side Impact Airbag Control Modules (SIACM)
over the PCI data bus. The SIACM notifies the ACM
when it has detected a monitored system fault and
stored a DTC in memory for its respective side cur-
tain airbag system, and the ACM sets a DTC and
controls the airbag indicator operation accordingly.
The ACM receives battery current through two cir-
cuits; a fused ignition switch output (run) circuit
through a fuse in the Integrated Power Module
(IPM), and a fused ignition switch output (run-start)
circuit through a second fuse in the IPM. The ACM
receives ground through a ground circuit and take
out of the instrument panel wire harness. This take
out has a single eyelet terminal connector that is
secured by a ground screw to the instrument panel
support structure. These connections allow the ACM
to be operational whenever the ignition switch is in
the Start or On positions. The ACM also contains an
energy-storage capacitor. When the ignition switch is
in the Start or On positions, this capacitor is contin-
ually being charged with enough electrical energy to
deploy the front 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. The
electronic impact sensor is an accelerometer that
senses the rate of vehicle deceleration, which pro-
vides verification of the direction and severity of an
impact. The safing sensor is an electromechanical
sensor within the ACM that provides an additional
logic input to the ACM microprocessor. The safing
sensor is a normally open switch that is used to ver-
ify the need for a front supplemental restraint
deployment by detecting impact energy of a lesser
magnitude than that of the electronic impact sensor,
and must be closed in order for the front airbags or
seat belt tensioners to deploy. A pre-programmed
decision algorithm in the ACM microprocessor deter-
mines when the deceleration rate as signaled by the
impact sensor and the safing sensor indicate an
impact that is severe enough to require front supple-
mental restraint system protection and, based upon
the status of the passenger airbag on/off switch input
and the severity of the monitored impact, determines
what combination of seat belt tensioner and front air-
bag deployment is required for each front seating
position. When the programmed conditions are met,
the ACM sends the proper electrical signals to deploy
the seat belt tensioners and dual front airbags.
The hard wired inputs and outputs for the ACM
may be diagnosed and tested using conventional
diagnostic tools and procedures. However, conven-
tional diagnostic methods will not prove conclusive in
the diagnosis of the ACM, the PCI data bus network,
or the electronic message inputs to and outputs from
the ACM. The most reliable, efficient, and accurate
means to diagnose the ACM, the PCI data bus net-
work, and the electronic message inputs to and out-
puts from the ACM requires the use of a DRBIII
t
scan tool. Refer to the appropriate diagnostic infor-
mation.
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,
SIDE CURTAIN AIRBAG, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT 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 PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
WARNING: THE AIRBAG CONTROL MODULE CON-
TAINS THE IMPACT SENSOR, WHICH ENABLES
THE SYSTEM TO DEPLOY THE FRONT SUPPLE-
MENTAL RESTRAINTS. NEVER STRIKE OR DROP
THE AIRBAG CONTROL MODULE, AS IT CAN DAM-
AGE THE IMPACT SENSOR OR AFFECT ITS CALI-
BRATION. 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 FRONT SUPPLEMEN-
TAL RESTRAINT DEPLOYMENT 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) On models with a manual transmission,
remove the floor console from the top of the floor
panel transmission tunnel. (Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - REMOVAL).
(3) On models with an automatic transmission,
remove the ACM cover from the instrument panel.
DR
RESTRAINTS 8O - 11
AIRBAG CONTROL MODULE (Continued)