warning SSANGYONG MUSSO 1998 Workshop User Guide

SECTION 8B
SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
Specifications . . . . . . . . . . . . . . . . . . . . . . . . 8B-1
General Specifications . . . . . . . . . . . . . . . . . . 8B-1
Schematic and Routing Diagrams . . . . . . . . 8B-2
Air Bag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8B-2
Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8B-3
Function Description . . . . . . . . . . . . . . . . . . 8B-4
Air Bag Module . . . . . . . . . . . . . . . . . . . . . . . . 8B-6
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8B-7
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . 8B-7
Self Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . 8B-10
Circuit Diagram . . . . . . . . . . . . . . . . . . . . . . . 8B-16
TABLE OF CONTENTS
Caution: Disconnect the negative battery cable before removing or installing any electrical unit or when a
tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable
will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise
noted.
SPECIFICATIONS
GENERAL SPECIFICATIONS
Application
Air bag System Deployment Time
Detection Time
Operating Temperature
Storage Temperature
Air Bag Replacement Interval
Voltage Range
Current Consumption
Acceleration Range
Max. Acceleration
Voltage Ramp
Energy Reservation
Inflator Ignition Energy
Squib Resistance
Air Bag Warning Lamp ON Time (When Ignition ON)Description
< 20ms
< 5ms
-40°C ~ +85°C
-40°C ~ +90°C
Every 10-year after installation
9-16V
5ms after ignition switch ON < 1A,
5ms ~ 5sec. <300mA, after 5sec. < 100mA
+/-50g
+/-600g pulse
0.5 ~ 2.0 V/s
150ms after battery disconnection
4.3mJ
2.15 ± 0.35 W
6 sec.
Air Bag Diagram . . . . . . . . . . . . . . . . . . . . . . 8B-17
Maintenance and Repair . . . . . . . . . . . . . . 8B-18
On-Vehicle Service . . . . . . . . . . . . . . . . . . . . . 8B-18
Air Bag Module . . . . . . . . . . . . . . . . . . . . . . . 8B-18
Clock Spring . . . . . . . . . . . . . . . . . . . . . . . . . 8B-19
Air Bag Control Unit (AC4) . . . . . . . . . . . . . . 8B-21
General Description and System
Operation . . . . . . . . . . . . . . . . . . . . . . . . 8B-22
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 8B-22
Caution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8B-22

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-3
CAUTIONS
Failure to follow the correct service procedure can cause air bag damage or personal injury due to unexpected air
bag deployment. Before service (removal and installation of part, check for replacement), please be weal noticed of
following items for your correct service.
1. For service, turn the ignition switch to ‘LOCK’ position and wait for 30 seconds after disconnecting the negative
battery cable.
2. If the vehicle collapsed, remove the air bag ECU first to reserve the crash records.
3, Never use other vehicles’ air bag components and replace with specified new part.
4. Never disassemble or repair the air bag module, air bag unit and wiring harness to re-use.
5. Replace the air bag module and air bag unit with new if it dropped, cracked or damaged.
6. Only qualified technicians in service shop should check or repair the air bag,
7. Before service, should be well noticed of warning labels on the vehicle.
A. Sun Visor Side
[Warning]
Pull down the sun visor and see SRS air bag
warning lamp on the head lining.
B. Head Lining
[Warning]
1 . This vehicle is equipped with air bag. Air bag is
supplemental device for the seatbelt. Fasten
your seatbelt.
2. This air bag should be replaced by authorized
supplier within replacement intervals.
3. When the ignition key is turned to ON position,
SRS warning lamp will turn on for 6 sec. and go
off. In this case, the system is normal.
For the following cases, see service manual.
- SRS warning lamp does not turn on.
- SRS warning lamp does not go off.
- SRS warning lamp continues to blink.
C. Steering Wheel Body Inner
[Warning]
Before removing the steering wheel, read service
manual first. Set the front wheels straight forward
and align the center position marks of SRS clock
spring. Improper removal or installation of the
steering wheel can damage the SRS components.D. Engine Compartment
[Warning]
This vehicle is equipped with air bag. Before
checking the engine compartment, read service
manual first. Faultuy check and service can cause
SRS air bag deployment and system defects that
can be led to severe damage.
E. Battery Cable
[Warning]
Before disconnecting the battery power, read
service manual first.

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-5
Input & Output Function
Electronic air bag control and diagnosis module is connected
by full 30-pin connectors.
Input : ground
Output : 1 squib line, warning lamp
Input/output : communication, diagnosis
16 Shorting Bar
17 Shorting Bar
18 Shorting Bar
19 Shorting Bar
20 Diagnosis
21 Shorting Bar
22 Shorting Bar
23 No Pin
24 No Pin
25 Shorting Bar
26 Shorting Bar
2 7 N/A
28 Shorting Bar
29 Shorting Bar
3 0 N/A 1 Lamp
2 Ground
3 N/A
4 N/A
5 Ignition
6 N/A
7 N/A
8 CONF
9 N/A
1 0 N/A
11 N/A
1 2 N/A
13 Squib Line 1(upper)
14 Squib Line 1(lower)
1 5 N/A
IGN
GND
Warning lamp
RxD/TxD
Inflator line 1
+
- 5
2
1
20
13
14
Air bag lamp
Communication/
diagnosis
Air bag
control
unit
Ground connection or open
Connector Pins
15
301
16

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-7
DIAGNOSIS
DESCRIPTION
Air bag control unit continuously controls system function as follows during ignition ON or driving.
- Recognition of collision
- Internal diagnosis
- External diagnosis
If recognize or detect defects, warning lamp will turn on. If there is danger of improper deployment, the system will
enter overall shutdown status and the air bag will not inflate.
Air bag control unit will store detected internal and external defects in the EEPROM.
System Control
Battery Voltage Check
Battery voltage will be monitored continuously. If voltage is out of normal operating range, all system diagnosis will
stop and warning lamp turn on.
Battery Voltage (V)
< 8.7
9 - 16
> 16.3
Function
System diagnosis stops and warning lamp turns on
Normal operation range
System diagnosis stops and warning lamp turns on
Squib Diagnosis
It checks not only high (4.50.5) or low (1.40.5) resistance but also short resistance (1- 10k) status between the
battery and ground to indicate defects in squib line by blinking warning lamp. Air bag control unit (AC4) can measure
squib resistance.
Warning Lamp Turning On
Air bag control unit detects system defects during ignition ON or driving and displays following 2 warning lamps.
- Warning lamp ON: internal defects of the air bag control unit
- Warning lamp blinking: higher resistance than standard in the squib line or short at the battery or ground,
Safety Function Check
It checks defects during operation of the arming sensor If the sensor is shorted for more than 2 seconds, the module
will enter overall shutdown mode.
Temperature Sensor
Function of the temperature sensor will be monitored continuously. If there is fault due to defective sensor or short,
the lamp will turn on and program will take calibration temperature (25) of collision conditions.
Power Supply
Airbag control unit operates in 9-16v and the characteristic of the system has backup condenser to supply the power
for max.150ms if there is power defect during collision.

8B-8 SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
Energy Reserve System
Energy reserve system is consisted of condensor and energy switch and will check following items continuously
during system operation.
- High voltage
- Low voltage
- Low rating capacity
- Function of the energy reserve switch
If there is fault in the energy reserve system, warning lamp will turn on. And defects are found by continuous
checking of the condenser voltage, the system will enter overall shutdown status for safety reason.
Shutdown Switch
There is 1 energy shutdown switch in the system and it will be checked during start-up. And it also checks that
condenser is discharging properly. If shutdown switch is short, it will be detected during condensor voltage test.
If squib line fault is obvious, the warning lamp will turn on and the module will enter overall shutdown status.
Accelerometer Check
Accelerometer function will be checked during start-up. During operation, accelerometer off-set signal will be checked,
If there is fault, module will enter overall shutdown status.
ASIC Overheat
Module monitors upper side ASIC overheats continuously. If overheated, the module will enter overall shutdown
status.
Microprocessor Fault
Module checks EEPROM, ROM checksum and RAM during start-up. EEPROM tests checksum operation.
If RAM or ROM checksum is defective, module will not allow start-up continuously but will be re-set,
If EEPROM is defective, warning lamp will turn on and the module will enter overall shutdown status.
During operation, RAM will continuously verify the proper operation of temporary memory program data usage. If
there is fault, the module will enter overall shutdown status and the warning lamp will turn on.
Watchdog Test
Watchdog function will be tested in start-up. If there is fault during the test, warning lamp will turn on and the module
will enter overall shutdown status.

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-9
Diagnosis
Air bag control unit diagnoses each function in the intervals of 250ms - 20 sec. during start-up or driving to prevent
unwanted air bag deployment. If there is defect, it turns on or blinks warning lamp to indicate defects in the air bag
system to the driver. And fatal defect is found, air bag control unit enters overall or partial shutdown status and fault
code will be stored.
Air bag control unit diagnoses following items.
- Ignition TR
- Acceleration
- Microprocessor, RAM and ROM
- Watchdog
- Shutdown Switch
Diagnosis Condition Diagnosis Items
Start-up (ignition ON)
During Driving
Lamp Blinking Mode
There are 2 kinds of blinking mode
1. When system internal fault is found, the lamp will stay on.
2. The lamp will blink according to external fault and there are 2 blinking codes.
Blinking code 1 (Squib resistance fault in the driver’s air bag squib line)
Blinking code 2 (Squib short on plus and minus in the air bag squib line)
Lamp blinking code is as follows. The last blinking will be within 0.5 sec. and 1 cycle of blinking will be repeated every
5 seconds.
Blinking Code 1
(Sec.) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Blinking Code 3
(Sec.) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
- Squib resistance
- Squib line short to battery and ground
- Energy reserve system
- Lamp output
- Battery voltage
- ASIC communication
- Arming sensor
- ASIC overheating
- RAM and W/D
- EEPROM

8B-14 SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
Fault
CodeDefectsService HintAppli-
cation
42 Over heat
4 3 SENS
44 Standard band gap
45 Temperature sensor
46 Warning lamp
47
Battery voltage
49 Fault code list
5 0 USA communication
51 LSA communication
52 No EEPROM program
53 EEPROM checksum
5 4 EEPROM map
55 External watchdog 1
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lOpen/short in the warning lamp circuit.
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lPower wire voltage is out of standard voltage (9
- 16V).
lCheck the battery for voltage and charging.
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lAir bag control unit internal defects.
lCheck the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
56 Arming sensor-no close
57 RAM check
5 8 System
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.
59 External watchdog 2
6 0 Pulse
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.

8B-22 SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
GENERAL DESCRIPTION
AND SYSTEM OPERATION
INTRODUCTION
SRS (Supplemental Restraint System) air bag protects driver
and passenger by inflating air bag under collision and seat
belt pre - tensioner is a supplemental equipment for seat belt
reducing shocks from the collision by pulling passenger’s body
against seat back at the same time of air bag inflation.
Air bag unit has diagnosis functions and indicates system
malfunctions to the driver by turning on the air bag warning
lamp.
CAUTION
Perform the service procedures for the air bag system as
ordered, if not, the air bag can be operated suddenly and it
could result in damage of air bag or injury. Before service
(removal, installation, checking and replacement of parts),
observe the following instructions and service correctly.
1. To service, turn the ignition switch to ‘LOCK’ position and
disconnect the negative battery cable and continue the
procedures after approx. 30 seconds.
2. If the vehicle is damaged due to accident, remove the air
bag ECU first to get the accident records.
3. Never use the other vehicle’s air bag parts and replace
with genuine part, if required.
4. Do not disassemble or repair the air bag module, air bag
unit and wiring harness to reuse.
5. Replace the air bag unit or air bag module if dropped,
cracked or damaged.

9A-6 BODY WIRING SYSTEM
Engine Room Fuse (EF) and Relay Box
1 Fuse (15A) : ABS, ABD
2 Fuse (20A) : Sun Roof
3 Fuse (10A) : Air Bag
4 Fuse (15A) : Audio, Clock, Out Side Mirror
5 Fuse (30A) : Cigarette lighter, Power Socket
6 Fuse (30A) : Heater
7 Fuse (15A) : Door Lock
8 Fuse (30A) : Rear Heated
9 Fuse (10A) : Audio, Buzzer, Chime, Clock
10 Fuse (30A) : Power Window
11 Fuse (10A) : Immobilizer
12 Fuse (20A) : T/C
13 Fuse (15A) : Interior Lamp
14 Fuse (15A) : Hazard Lamp
15 Fuse (15A) : Stop Lamp
16 Fuse (15A) : Turn signal Lamp, Head Lamp
17 Fuse (10A) : Back up Lamp
18 Fuse (15A) : Cluster, STICS
19 Fuse (15A) : A/T, Diagnosis
20 Fuse (15A) : Over Voltage Protection Relay
(Gasolin Only)
21 Fuse (15A) : Seat Heater
22 Fuse (15A) : ECS
23 Fuse (15A) : Front Wiper & Washer
24 Fuse (10A) : Rear Wiper & Washer, A/C
25 Relay : Front Wiper26 Relay : ABS Warning Lamp
27 Relay : Flasher Unit
28 Relay : Fuel Pump (Gasoline Only)
29 Relay : Shift Lock (A/T)
30 Relay : Clutch Interlock & Neutral
31 Relay : Sun Roof
32 Relay : A/T ‘B’ Interlock (MB A/T)
33 Relay : Power Window
34 Relay : Rear Fog Lamp
35 Relay : ECS
36 Relay : Compressor (Diesel E/G)
Condenser Fan (Gasoline E/G)
37 Relay : Condenser Fan
38 Relay : Air Conditioner
39 Fuse (10A) : Tail Lamp
40 Fuse (15A) : Head Lamp(LH)
41 Fuse (15A) : Head Lamp(RH)
42 Fuse (15A) : Front Fog Lamp
43 Fuse (10A) : Horn
44 Fuse (10A) : Compressor
45 Relay : Resistor with Diode (Gasoline E/G)
46 Relay : Front fog Lamp
47 Relay : Condenser Fan
48 Relay : Tail Lamp
49 Relay : Horn

9A-8 BODY WIRING SYSTEM
1 Fuse Box
2 Door Lock Relay
3 Relay Box
3.1 Front Wiper Relay
3.2 ABS Warning Lamp Relay....................................ABD 5.0
3.3 Flasher Unit
3.4 Fuel Pump Relay.................................................Gasoline E/G
3.5 Shift Lock Relay...................................................Automatic Transmission
3.6 Clutch Interlock & Neutral Relay...........................Manual Transmission or Automatic Transmission
3.7 Sun Roof Relay
3.8 Automatic Transmission ‘B’ Switch Interlock.......Automatic Transmission
3.9 Power Window Relay
3.10 Rear Fog Lamp Relay..........................................Rear Fog Lamp
3.11 ECS Relay
4 Defogger Relay
5 Ground 1
6 Roof Wiring Connector
7 Diode 1
8 Front Door Wiring Connector
9 Front Door Wiring Connector
10 Front Door Wiring Connector
11 Front Door Wiring Connector
12 Kick Down Relay..................................................Automatic Transmission
13 Floor Wiring Connector
14 Floor Wiring Connector
15 Floor Wiring Connector
16 ABD Floor Wiring Connector................................ABD 5.0
17 ECS Floor Wiring Connector
18 Rear Iper & Washer Switch
19 Clutch Switch........................................................Manual Transmission
19-1Clutch Switch........................................................E32 Gasoline E/G with Manual Transmission
20 Stop Lamp Switch
21 Outside Mirror Switch
22 Ignition Switch
23 Multi Function Switch
24 Multi Function Switch
25 Black Out Switch..................................................Black Out Lamp
26 Black out switch...................................................Black Out Lamp
27 Joint Connector (Tail)
28 Joint Connector (Ignition)
29 Cluster
30 Cluster .................................................................Automatic Transmission
31 Cluster
32 Cluster
33 4WD Switch..........................................................Except TOD
33-14WD Switch.......................................................... TOD
3 4 Hazard Switch
35 Ground 2
36 Pedal Module.......................................................Gasoline E/G with MSE ECU
37 Audio Switch
3 8 Immobilizer...........................................................Crypto Type, Gasoline E/G with MSE ECU or Diesel E/G
39 Ignition Switch
40 Multi Function Switch
4 1 STICS
4 2 STICS
4 3 REKES.................................................................Remote Keyless