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-10 SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
1. Position the ignition switch to ‘OFF’.
2. Connect the harness connector of scanner to the diagnosis
socket in engine compartment.
3. Turn the ignition switch to ‘ON’ position.
4. Select “Electronic control vehicle diagnosis” from function
selection display and press ‘Enter’.
5. Select “Musso (’98 model year)” from vehicle model
selection display and press ‘Enter’.
6. Select “Electronic air bag” from control system selection
display and press ‘Enter’.
7. Select “Self-diagnosis” from diagnosis item selection display.
Notice
Check sensor value of output display, if necessary.
8. Determine the fault code and trace defective component.
Notice
Refer to self-diagnosis list.
SELF DIAGNOSIS
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-20 SUPPLEMENTAL RESTRAINT SYSTEM(SRS)
Removal & Installation Procedure
preceding work : removal of steering wheel
1. Turn the ignition switch to “OFF” position and disconnect
the battery negative cable. Start the procedure after waiting
over 3oseconds.
2. Unscrew 3 screws from lower cover on steering column shaft
and remove the lower cover.
3. Unscrew 4 screws from clock spring and remove the clock
spring
Installation Notice
lDon’t try to repair and modify the clock spring.
lWhen aligning the neutral position, turn to clockwise until it
stops, and turn to counter clockwise until the marks are
aligned
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.
SECTION 9A
BODY WIRING SYSTEM
Schematic and Routing Diagrams . . . . . . . . 9A-2
Power Distribution . . . . . . . . . . . . . . . . . . . . . . 9A-2
Starting & Charging (Gasoline HFM) . . . . . . . 9A-3
Starting & Charging (Diesel) . . . . . . . . . . . . . . 9A-4
Fuse Box and Relay . . . . . . . . . . . . . . . . . . . 9A-5
Location of Connectors by
Wiring Harness . . . . . . . . . . . . . . . . . . . . . 9A-7
Main . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9A-7
Engine Room . . . . . . . . . . . . . . . . . . . . . . . . 9A-11
Floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9A-13
Roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9A-14
Driver's Door . . . . . . . . . . . . . . . . . . . . . . . . . 9A-15
Passenger's Door . . . . . . . . . . . . . . . . . . . . . 9A-15
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.
Rear Left Door . . . . . . . . . . . . . . . . . . . . . . . 9A-16
Rear Right Door . . . . . . . . . . . . . . . . . . . . . . 9A-16
Tail Gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9A-17
Semi Automatic Air Conditioner . . . . . . . . . . 9A-18
Full automatic Air Conditioner . . . . . . . . . . . . 9A-19
Gasoline Engine (MSE) . . . . . . . . . . . . . . . . 9A-20
Gasoline Engine (HFM) . . . . . . . . . . . . . . . . 9A-21
Diesel Engine . . . . . . . . . . . . . . . . . . . . . . . . 9A-22
Manual Transmission . . . . . . . . . . . . . . . . . . 9A-23
Automatic Transmission (BENZ) . . . . . . . . . . 9A-24
Automatic Transmission (BTRA) . . . . . . . . . . 9A-25
Driver's Seat . . . . . . . . . . . . . . . . . . . . . . . . . 9A-26
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