sensor SSANGYONG KORANDO 2013 Service Manual

3. AIR BAG SYSTEM OPERATING PROCESS
1) Air Bag System Input/Output
The air bag unit (SDM) performs the internal/external diagnosis on the air bag system for about 6
seconds after IGN ON. The air bag unit is ready to deploy air bag after this diagnosis, and when a
certain level of collision occurs, it determines the deployment of the air bag using the signals from the
impact sensors, deploys the corresponding air bag, and stores the collision data and EDR data. The
body control module (BCM) activates the auto door unlock function and various lamps including hazard
warning lamp and room lamps, when the crash signal from the SDM is received to notify others of
emergency situation and let the occupant escape easily.
Major functions
Detects frontal and side collision (Rear-end collision only with EDR trigger)
Activates the front air bag, side air bag, curtain air bag and belt pretensioners
Indicates system readiness and faults to the driver by means of a fault warning lamp
Facilitates servicing capability via a serial diagnostic communication interfaces
Records crash data and DTCs
Keeps power for deployment of air bag even when the power to the air bag unit is cut off due to the
collision
Event data recorder (EDR) -
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The air bag will be deployed when:
The air bag can be deployed when:
the impact or type of a frontal collision is too much for the seat belt to protect the occupant. -
a collision to diagonal direction (not a frontal collision) occurs or the vehicle tips over.
a minor collision which the air bag sensor cannot detect occurs (impact is lower than that of
operating condition).
a collision against narrow objects, such as a telegraph pole or a tree, occurs.
the vehicle goes into a drainage or a puddle.
the vehicle wedges under a truck or a trailer or collides with the underbody of a heavy-duty
vehicle.
the hood is hit by falling stones.
the air bag warning lamp is on. -
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-the vehicle rolls over or tips over sideward, or a side/rear collision occurs.
the impact of the collision is low enough for the seat belt to protect the occupant properly. -
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The air bag will be hardly deployed when:
2) Front Air Bag System Operating Process
(1) Front air bag system deployment conditions
there is underbody impact from the road surface, impact against the curb at a very high speed, or
dropping impact onto the road surface with a large angle. -
The air bag will not be deployed when:
(2) Front air bag system deployment
When a collision occurs the air bag unit receives the signal from the front impact sensor and ignites the
front air bag to deploy the driver and passenger air bags and seat belt pretensioner.
Item Impact to (front)
Driver air bag Ignite
Passenger air bag Ignite
Seat belt pretensioner - Driver side Ignite
Seat belt pretensioner - Passenger side Ignite
(3) Component change after deployment
Air bag unit and its wirings (including connectors), seat belt pretensioner and its wirings (including
connectors), all front air bags, instrument panel, front impact sensor and other damaged components

(2) Side air bag system deployment
The side air bag system is activated in the event of a left side or right side collision. The seat side air bags
are installed to the driver and passenger seat (one on each seat) and the curtain air bags are installed in
the end of the roof located on the upper sides of both doors. The side air bags and the curtain air bags are
operated by the same signal. The air bags of the driver seat and passenger seat are operated separately
according to the impact position (left side, right side).
ItemImpact to (side)
LH RH
Side air bag - Driver side Ignite Not ignite
Side air bag - Passenger side Not ignite Ignite
Curtain air bag - Driver side Ignite Not ignite
Curtain air bag - Passenger side Not ignite Ignite
Seat belt pretensioner - Driver side Not ignite Not ignite
Seat belt pretensioner - Passenger side Not ignite Not ignite
(3) Component change after deployment
Side air bag deployed
Deployed side air bag, air bag unit and its wirings (including connectors), side impact sensor, other
damaged trim, seat components
Curtain air bag deployed
Deployed curtain air bag, air bag unit and its wirings (including connectors), side impact sensor,
damaged trim, seat and roof headlining

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General deployment of air bag
3) Deployment Procedure
Air bag cover (opening section)
Air bag cushion
Vent hole
Inflator
Filter
Ignition
Gas generator In general, the air bag unit transmits the ignition current to the ignition device of the corresponding air bag
inflator when a collision signal from the impact sensor is sent to the air bag unit
When the ignition device of the inflator is ignited, the gas generator generates nitrogen gas by being
burned, and this gas inflates the air bag cushion through the filter. The nitrogen gas used to inflate the air
bag exhausts through the vent hole immediately.
Cross section of driver air bag
Cross section of inflator

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4) Air Bag Deployment Signal to BCM
The air bag deployment signal from the air bag unit is sent to the BCM. This signal triggers the flash of
the hazard warning lamp to notify others of emergency situation, and is used as a signal that turns on the
room lamps and activates auto door unlock function for the occupants.
The air bag unit of a vehicle without side air bag system can also send the crash signal to the BCM
according to the value of the acceleration sensor to activate the auto door unlock and various lamps
including hazard warning lamp and room lamps.

4. AIR BAG SYSTEM SELF DIAGNOSIS
1) Air Bag Unit (SDM) Self Diagnosis
The air bag unit monitors the internal/external devices of the air bag system including battery voltage,
limits certain functions of the air bag, and turns on the air bag warning lamp on the instrument cluster
according to the conditions.
Conditions for detecting and clearing faults
The time for detecting errors and clearing the errors is as follows:
Monitoring system Diagnosis
cycleTime for
detectingTime for
clearingClearing fault
Inflator circuit 400 ms 4 seconds 8 seconds with a diagnostic device
warning lamp circuit 100 ms 4 seconds 8 seconds with a diagnostic device
Battery voltage 10 ms 4 seconds 4 seconds with a diagnostic device
Impact sensor IGN ON 1 seconds2 to 4
seconds
(next Ign)with a diagnostic device
Impact record
(air bag deployed)-
Immediately-
by replacing SDM
(cannot be cleared with a
diagnostic device)
SDM internal fault--
by replacing SDM
(cannot be cleared with a
diagnostic device)

4) Internal monitoring
The air bag unit checks the status of the air bag system and monitors the system for internal errors. If
an error is detected by self diagnosis, this unit disables part of the air bag system functions and outputs
a diagnostic trouble code (DTC) and air bag warning lamp signal.
Watchdog
The micro controller is monitored periodically. And if a fault is found, micro controller is reset, inflator
ignition function is limited, and the air bag warning lamp comes on. -
Air bag operations for errors
Internal errorsAir bag operation
Front air bag system Side air bag system
X-axis acceleration sensor
error
DisabledDisabled
Y-axis acceleration sensor
errorDisabled
Z-axis acceleration sensor
erroravailable
ROM checksum error Disabled
RAM checksum error Disabled
NVM checksum error Disabled
Internal acceleration sensor test
The air bag unit checks internal acceleration sensor when the ignition is turned on. The air bag unit
determines the deployment of the air bag for the collision signal input after the diagnosis. -
Non-volatile memory (NVM) test
The air bag unit checks the values stored in the memory. If the values are not correct, the air bag unit
sets a diagnostic trouble code (DTC) and turns on the air bag warning lamp. -

Impact sensor monitoring
The air bag unit supplies a certain level of test current to monitor the front and side impact sensors. If the
wiring is open/short circuited or no signal is input, or communication is malfunctioning, it sets a DTC and
turns on the air bag warning lamp.
FaultsDetection
Time for clearing
Fault condition Time for detecting
Normal errorsIncorrect ID after IGN ON
Approx. 1 seconds.Approx. 2 seconds.
(next Ign) Faulty sensor after IGN ON
Communication error
Incorrect ID Inconsistent ID after IGN ON
Communication
errorCommunication data error
Approx. 2 seconds.
Open/Short circuit (B+)
Short Circuit to
GroundShort Circuit to Groundapprox. 2 to 4
seconds
6) DTC and Air Bag Deployment Data Storing
DTC storing
Airbag deployment data storing
The air bag deployment data due to a collision cannot be cleared. The air bag unit should be
replaced. -
- All DTCs of air bag system are stored in the air bag unit. Maximum number of DTCs that can be stored
is 16. If a new DTC is set after 16 DTCs are stored, the oldest stored code is erased first.
The air bag deployment data is stored in the air bat unit. Maximum number of data that can be stored is
7.

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5. EVENT DATA RECORDER (EDR)
The event data recorder (EDR) stores the driving information data in a crash or near crash event, when
the acceleration sensor in the air bag unit detects a sharp acceleration change which meets the EDR
operating conditions, regardless of the air bag deployment The air bag unit always stores the driving
information data and updates the data with new one periodically. If a collision is detected by front and
side impact sensors, the acceleration sensor in the SDM detects the change in acceleration. The air bag
unit stores the information on internal acceleration sensor, driving status and air bag deployment at this
time.
The EDR stores the driving information also when the acceleration sensor in the air bag unit detects
a sharp acceleration change in the event of a rear-end collision or side collision for a vehicle without
an air bag

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The front part of the active head restraint is separated and moved forward to protect the occupant's neck
in the event of a rear-end collision.
The active head restraints may be installed to both driver and passenger seats depending on the vehicle
specifications.
(1) System configuration
Active head restraint sensor
Active head restraint
(passenger seat)
Active head restraint
(driver seat)
2) Active Head Restraint