ECU SSANGYONG MUSSO 1998 Workshop Repair Manual

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-11
Self-Diagnosis List
Fault
CodeDefectsService Hint
01 Driver’s squib (+) side No. 1
lShort of (+) side No. 1 in the driver’s squib circuit.
lCheck connection of connector.
lCheck the ECU.
Appli-
cation
02 Driver’s squib (+) side No. 2lShort of (+) side No. 2 in the driver’s squib circuit.
lCheck connection of connector.
lCheck the ECU.
X
03 Driver’s squib (+) side No. 3lShort of (+) side No. 3 in the driver’s squib circuit.
lCheck connection of connector.
lCheck the ECU.
X
04 Driver’s squib (+) side No. 4X
05 Driver’s squib ground (-) side No. 1lShort of ground side No. 1 in the driver’s squib
circuit.
lCheck and replace the ECU.
06 Driver’s squib ground (-) side No. 2lShort of ground side No. 2 in the driver’s squib
circuit.
lCheck and replace the ECU.
X
07 Driver’s squib ground (-) side No. 3lShort of ground side No. 3 in the driver’s squib
circuit.
lCheck and replace the ECU.
X
08 Driver’s squib ground (-) side No. 4lShort of ground side No. 4 in the driver’s squib
circuit.
lCheck and replace the ECU.
X
09 Energy shutdown switch No. 1lAir bag control unit internal defects.
lCheck and replace the ECU.
10 Energy shutdown switch No. 2lAir bag control unit internal defects.
lCheck and replace the ECU.
X
11 Energy shutdown switch No. 3lAir bag control unit internal defects.
lCheck and replace the ECU.
X
12 Energy shutdown switch No. 4lAir bag control unit internal defects.
lCheck and replace the ECU.
X
13 Ignition switch wire No. 1lAir bag control unit internal defects.
lCheck and replace the ECU.
14 Ignition switch wire No. 2lAir bag control unit internal defects.
lCheck and replace the ECU.
X
15 Ignition switch wire No. 3lAir bag control unit internal defects.
lCheck and replace the ECU.
X
16 Ignition switch wire No. 4XlAir bag control unit internal defects.
lCheck and replace the ECU.

8B-12 SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
Fault
CodeDefectsService HintAppli-
cation
17 Squib No. 1 resistance
18 Squib No. 2 resistanceX
19 Squib No. 3 resistanceX
20 Squib No. 4 resistanceX
21 Squib No. 1 resistance
22 Squib No. 2 resistanceX
lDriver’s squib resistance is higher than standard
(4.5±0.5W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
lDriver’s squib resistance is higher than standard
(4.5±0.5W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
lDriver’s squib resistance is higher than standard
(4.5±0.5W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
lDriver’s squib resistance is higher than standard
(4.5±0.5W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
lDriver’s squib resistance is lower than standard
(1.4±0.3W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
lDriver’s squib resistance is lower than standard
(1.4±0.3W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
23 Squib No. 3 resistanceXlDriver’s squib resistance is lower than standard
(1.4±0.3W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-13
Fault
CodeDefectsService HintAppli-
cation
24 Squib No. 4 resistance
X
25 Energy reserve No. 1 voltage
26 Energy reserve No. 2 voltageX
27 Energy reserve No. 3 voltageX
28 Energy reserve No. 4 voltageX
29 Energy reserve No. 5 voltage
30 Energy reserve No. 6 voltage
31 Energy reserve No. 1 current off
capacity
32 Energy reserve No. 2 current off
capacityX
33 Energy reserve No. 3 current off
capacityX
34 Energy reserve No. 4 current off
capacityX
35 Energy reserve No. 5 current off
capacity
36 Condensor voltage
37 Collision times checksum
lDriver’s squib resistance is lower than standard
(1.4±0.3W).
lCheck related circuits for open/short.
lCheck connection of connector.
lCheck the ECU.
lReplace the squib wire.
lPlus side short : 7k, ground side short : 6kW.
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.
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.
lAir bag control unit internal defects.
lCheck and replace the ECU.
4 1 Major USAlAir bag control unit internal defects.
lCheck and replace the ECU. 38 Driver’s acceleration sensor
39
Driver’s acceleration sensor off-set
40 Arming sensor
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.

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.

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-15
Fault
CodeDefectsService HintAppli-
cation
127 Collision signal
128 Collision number
lAir bag control unit internal defects.
lCheck and replace the ECU.
lAir bag control unit internal defects.
lCheck and replace the ECU.

SUPPLEMENTAL RESTRAINT SYSTEM(SRS) 8B-21
AIR BAG CONTROL UNIT(AC4)
Removal & Installation Procedure
AC4 is installed on the center portion of the front floor tunnel.
Built-in accelerometer sensor detects collision and determines
action or non-action and ignition time.
Notice
Do not disassemble the AC4 to repair. If defective, replace it.
AC4 should not be shocked or vibrated by dropping on the
ground or bumping.
Replace the AC4 with new after air bag inflation.
1. Disconnect the negative battery cable and wait for 30
seconds before starting service.
Notice
Though battery cable is disconnected, air bag control unit
will maintain backup power for 150ms and air bag can be
inflated, so wait for min.30 seconds.
2. Remove the console box and center fascia panel assembly.
3. Remove the heater control switch and audio assembly.
4. Remove the lower side panel of the driver’s portion and
glove box.
5. Remove the lower main panel.
6. Release the lock lever of the AC4 connector and disconnect
the connector.
7. Unscrew 3 nuts and remove the AC4.
Notice
For installation, horizontal position should be secured for
the better changes of collision pulse between the vehicle
body and air bag control unit.
8. Installation should follow the removal procedure in the
reverse order.
Inspection Procedure
1. Check AC4 case and welt bolts for crack or deformation.
2. Check connector, lock lever and terminal for deformation.
Notice
Replace the AC4 with new if dust, deformation or corrosion
found.

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-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

BODY WIRING SYSTEM 9A-9
44 Joint Connector.................................................... Ground
45 Door Unlock Switch
46 Front Fog Lamp Switch
47 Rear Defogger Switch
4 8 ECS Switch
49 Rear Fog Lamp Switch........................................Rear Fog Lamp
50 Digital Clock
51 Thermo Amplifier
52 Glove Box Lamp Switch
53 Air Conditioner Wiring Connetor
54 Glove Box Lamp
55 Ground 6
56 Ground 6.............................................................Gasoline E/G
57 Ground 7.............................................................Gasoline E/G
58 Wheel Speed Sensor (FR)..................................ABS 5.0 or ABD 5.0
59 O
2 Sensor............................................................E32 Gasoline E/G
60 Engine Main Wiring Connector............................Gasoline E/G with MSE ECU
61 HFM .....................................................................Gasoline E/G with HFM ECU
61-1 MSE .....................................................................Gasoline E/G with MSE ECU
62 Front Door Wiring Connector (Passenger Side)
63 Front door Wiring Connector (Passenger Side)
64 Joint Connector (B+)
65 Audio
66 Audio
67 Air Bag Wiring Connector
68 Chime Bell
6 9 Buzzer
70 Kick Down Switch.................................................Automatic Transmission
71 Diode 2................................................................Manual Transmission
72 Ground 3
73 Ground 4
74 Front Cigarette Lighter
75 Diode 3................................................................Automatic Transmission, MB
76 S/E Mode Selector Switch....................................Automatic Transmission
76-1Mode Switch........................................................Automatic Transmission
77 “B” Position Switch..............................................Automatic Transmission
78 “P” Position Switch..............................................Automatic Transmission
79 Shift Lock Solenoid Valve.....................................Automatic Transmission
8 0 TCCU
81 Ground 5.............................................................Gasoline E/G
81-1Ground 7.............................................................Diesel E/G
82 Seat Extension Wiring Connector
83 Transmission Extension Wiring Connector...........E23 & E32 Gasoline E/G with Manual Transmission
83-1 Transmission Extension Wiring Connector...........Diesel E/G with MB A/T
84 Transmission Extension Wiring Connector...........Gasoline E/G with Manual Transmission
84-1 Transmission Extension Wiring Connector...........Diesel E/G with Manual Transmission or BTRE A/T
85 Transmission Extension Wiring Connector...........E23 & E32 Gasoline E/G with A/T
85-1 Transmission Extension Wiring Connector...........Diesel E/G with BTRE A/T
86 Transfer Case Motor
87 Transfer Case Motor
88 Vehicle Speed Sensor
89 Fuel Gauge
90 Acceleration Sensor.............................................ABS 5.0
91 Seat Belt Switch (Passenger)
92 Seat Heater Switch
93 Head Lamp Leveling Device Switch.....................Leveling Device