501-20B-7
Occupant Restraints — Passive — Supplemental Air
501-20B-7
Bag System
DIAGNOSIS AND TESTING (
CONTINUED
)
Air Bag Control Module
The air bag control module is mounted
horizontally to the crossmember beneath the
centre console, to facilitate impact sensing along
the longitudinal axis. The air bag control module
retains full control of the whole system, providing
continual system checks and full diagnostic
capabilities. The non-volatile memory stores the
fault codes, which can then be downloaded
through the data link connector (DLC) to WDS. A
visual warning indicator, which is housed within
the instrument cluster, is illuminated when the
ignition is switched ON for approximately three
seconds then goes out. If a fault occurs the
warning indicator, depending on the nature of the
fault, begins to flash or illuminates continuously
after five seconds.
In the event of a failure in the vehicle power
supply during or after an accident, the air bag
control module provides an auxiliary power
supply, sufficient to deploy the air bag(s) for a
minimum of 150mS. The air bag control module
discharges the back up power supply within 60
seconds of the battery ground cable being
disconnected. Thus making sure the
supplemental restraint system remains
operational.
The air bag control module contains a micro-
controller to evaluate and process impact data
and two micro machine sensors. An electronic
accelerometer, which converts the actual
acceleration and deceleration force, along the
vehicles longitudinal axis into electrical signals.
When both these sensors sense an impact in
excess of a predetermined limit, the air bag
control module initiates the circuit to deploy the
frontal air bags. The two micro machine sensors
prevent unintentional deployment of the frontal air
bags.
Air Bag Warning Indicator
The air bag warning indicator is incorporated into
the instrument cluster, together with the
automatic detach detect (ADD) circuit, the air bag
warning indicator comes on for three seconds at
key ON. If the system self-tests OK the indicator
goes out, if a fault is detected the indicator will
flash after five seconds, illuminate continually
from key ON or not illuminate at all, depending on
the nature of the fault.
The ADD circuit is designed to illuminate the air
bag warning indicator continuously, if the air bag
control module circuit is broken, either by loss of
power or ground supply. The air bag control
module retaining bolts are part of the ground
circuit.
Diagnostic evaluation of the supplemental
restraints system can be made through the data
link connector (DLC) and WDS to establish the
nature of the concern. Once the diagnostic
trouble code (DTC) is known the appropriate
course of action can be selected from the
Symptom Chart.
08/2001
2002 Bantam
