System Components - Dodge ZB 2005 Service Manual

GENERAL INFORMATION
3.1 AIRBAG SYSTEM
The ZB Airbag System contain the following
components: Occupant Restraint Controller (ORC),
Airbag Warning Indicator, Clockspring, Driver and
Passenger dual stage Airbags, Driver and Passen-
ger Hall-effect Seat Belt buckles Switches (SBS),
Driver and Passenger Seat Belt Tensioners (SBT)
and a Passenger Airbag On-Off Switch.
The Occupant Restraint Controller (ORC) is a
new type of Airbag Control Module (ACM). The new
ACM supports staged airbag deployment. Staged
deployment is the ability to trigger airbag system
squib inflators individually as needed to provide the
appropriate restraint for the severity of the impact.
The ACM has four major functions: PCI Bus com-
munications, onboard diagnostics, impact sensing,
and component deployment. The ACM also contains
an energy-storage capacitor. This capacitor stores
enough electrical energy to deploy the front airbag
components for two seconds following a battery
disconnect or failure during an impact. The ACM is
secured to the floor panel transmission tunnel un-
der the console. The ACM cannot be repaired or
adjusted. The ACM sends and/or receives PCI Bus
messages with the Instrument Cluster (MIC), Body
Control Module (BCM).
The microprocessor in the ACM monitors the
impact sensors signals and the airbag system elec-
trical circuits to determine the system readiness. If
the ACM detects a monitored system fault it sends
a message to the instrument cluster via PCI bus to
turn on the airbag warning indicator. The ACM can
set both active and stored diagnostic trouble codes
to aid in the diagnosing system problems. See
DIAGNOSTIC TROUBLE CODES in this section.
The ACM uses two front impact sensors and ACM
Accelerometer to sense the rate of vehicle decelera-
tion, provide verification of the direction and sever-
ity of an impact. A pre-programmed decision algo-
rithm in the ACM microprocessor determines when
the deceleration rate is severe enough to require
airbag system protection. The ACM also uses the
driver and front passenger seat belt switch status
(buckled or unbuckled) and crash severity to deter-
mine the level of driver and front passenger airbag
deployment, low medium or high. When the pro-
grammed conditions are met, the ACM sends an
electrical signal to deploy the appropriate airbag

system components.

WARNING: THE AIRBAG SYSTEM IS A
SENSITIVE, COMPLEX ELECTRO-MECHANI-
CAL UNIT. BEFORE
DIAGNOSE OR
SYSTEM OR RELATED STEERING WHEEL,
STEERING COLUMN,
PANEL COMPONENTS YOU MUST FIRST
DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE. WAIT TWO
MINUTES FOR THE SYSTEM CAPACITOR TO
DISCHARGE BEFORE FURTHER SYSTEM
SERVICE. THIS IS THE ONLY SURE WAY TO
DISABLE THE AIRBAG SYSTEM. FAILURE
TO DO THIS COULD RESULT IS ACCIDENTAL
AIRBAG DEPLOYMENT
PERSONAL INJURY. NEVER STRIKE OR
KICK THE AIRBAG CONTROL MODULE, AS
IT CAN DAMAGE THE IMPACT SENSOR OR
AFFECT ITS CALIBRATION. IF AN AIRBAG
CONTROL MODULE
DROPPED DURING SERVICE, THE MODULE
MUST BE SCRAPPED AND REPLACED WITH
A NEW UNIT. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND
PERSONAL INJURY OR DEATH.
The airbag warning indicator is the only point at
which the customer can observe symptoms of a
system malfunction. Whenever the ignition key is
turned to the run or start position, the ACM per-
forms a lamp check by turning the airbag warning
indicator on for 6 to 8 seconds. After the lamp check,
if the indicator turns off, it means that the ACM has
checked the system and found it to be free of
discernable malfunctions. If the lamp remains on,
there could be an active fault in the airbag system
or the MIC airbag warning lamp circuit may be
internally shorted. If the lamp comes on and stays
on for a period longer than 6 to 8 seconds then goes
off, there is usually an intermittent problem in the
system.
3.1.1 DRIVER AIRBAG
The airbag protective trim cover is the most
visible part of the driver side airbag system. The
protective trim cover is fitted to the front of the
airbag module and forms a decorative cover in the
center of the steering wheel. The module is
mounted directly to the steering wheel. The module
is mounted directly to the steering wheel. Located
under the trim cover are the horn switch, the airbag
cushion, and the airbag cushion supporting compo-
nents. The airbag module includes a housing which
the cushion and hybrid inflator are attached and
sealed. The ZB is equipped with driver airbag with
2
ATTEMPTING
SERVICE ANY AIRBAG
OR INSTRUMENT
AND POSSIBLE
IS ACCIDENTALLY
TO