airbag off LEXUS SC400 1991 Service Owner's Manual

YESNO
INSPECTION PROCEDURE
1Preparation.
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, andwait at least 90 seconds.
3. Connect battery negative (±) terminal cable.
4. Disconnect center airbag sensor assembly con- nector.
5. Turn ignition switch ON. But do not start engine.
6. Measure voltage at IG
2 or ACC on connector wire
harness side of center airbag sensor assembly and
operate electric system (defogger, wiper, headlight,
heater blower, etc.)
Voltage: 6 V ± 11.5 V at IG
2 and ACC.
7. Turn electric system switch OFF.
8. Turn ignition switch LOCK.
9. Disconnect battery negative (±) terminal cable, and wait at least 90 seconds.
10. Remove voltmeter and connect center airbag sen- sor assembly connector.
11. Connect battery negative (±) terminal cable.
2Does SRS warning light turn off after approx. 10 seconds?
C
PTurn ignition switch ACC or ON and wait at least 20 sec-
onds.
Clear malfunction code. Turn ignition switch LOCK and
wait at least 20 seconds.
Operate electric system checked in
(5) and check
that SRS warning light goes off after approx. 10 sec-
onds.
Check diagnostic trouble code, and if a malfunction code
is output, perform trouble shooting according to mal-
function code. If a normal code is output, replace center
airbag sensor assembly.
Check battery and charging system.
(See page CH±1)
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±69
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DTC22SRS Warning Light System Malfunction
CIRCUIT DESCRIPTION
The SRS warning light is located on the combination meter.
When the supplemental restraint system is normal, the SRS warning light ligh\
ts up for approx. 6 seconds after
the ignition switch is turned from LOCK position to ACC or ON position, and then turn\
s off automatically. If there
is a malfunction in the supplemental restraint system, the SRS warning l\
ight lights up to inform the driver of the
abnormality.
When terminals Tc and E
1 of the DLC2 are connected, the diagnostic trouble code is displayed by the blinking
of the SRS warning light.
The SRS warning light circuit is equipped with an electrical connection che\
ck mechanism which detects when
the connector to the center airbag sensor assembly is not properly connecte\
d.
If the connector to the center airbag sensor assembly is not properly conn\
ected, the SRS warning light will not
light up.
Diagnostic trouble code 22 is recorded when a malfunction occurs in the SRS warnin\
g light system. If an OPEN
malfunction occurs in the SRS warning light system, the SRS warning light does not light up, so that until the
malfunction is repaired, the diagnostic trouble codes (including 22) c\
annot be confirmed.
DTC No.Trouble Area
22 Open circuit in SRS warning light system.
 Center airbag sensor assembly malfunction.
RS±102±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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567 8
21 LEXUS SC300(
Cont ' d )
AIR BAG
CHA RGE
OIL
OIL LEVEL COOLANT
LEVEL REAR
LI GHT
PWR
ABS TRAC
TRAC OFF
CRUISE WASHER
O/ D OFF
FUEL
SEAT BELTP
R N D 2 L
A
C
C A
A
B
B
B
C
C
C
C
C
C
C
B C
C
B
B
BA
B
A
A
C
CA A A A A A A A
C
C
C
C C C A C C B B B B
B A A C C
10 : 00
BK 1E
18 3D
10
3A
1
1J
1 1K
12
IH IF ED
IK1
8
IK2 IK1
9
1
E
3
E
2
E
1
D
BU110
BU1
3
BU1
4 11
11
1
14
19
8
18
11
13 6
18
17
16
20
19
15
13
3
15 5
1
20 9
18 8
11
87 1 2 3 4 5 16 17
2
3
4
5 10 9
12 23 12 4 17 16 7
6
15
10 22 21
W± R
RY
B±O
Y±B
V± R
V±Y
R±W
L±R
W
R± Y B
V±W V
R
L±R
P±L
Y±B
B±Y
B± W
W±B BR
B
W± B W± B BR±B
Y± G
B
Y±G
BR±B
W± B
W±B
W±B
BR±B W± B BR
Y±G
WATER
TEMP.HI GH BEAM TURN
LH
RH
BRAKE DOOR
TACHO
TRI P
SPEED
ILLUMINATIONCHECK±
ENGINE
FUEL
See Taillight and
St op Light Sy stem
<4±6><5±6>
SeeEngineControlSystem
<2±3>
Se e ABS Sy st e m< 8± 7> < 9± 3>
See Cruise Control System
< 16±3>Se e ABS an d Tr act io n
Control System< 8±7>
SeeECTandA/TIndicator
System< 3±5>
D
F1 7 , F18 E
FUEL SENDER Y±B
B±Y
B±W 24
See SRS Airbag System< 15±4>
See Charging Sy stem< 1±2>
See Headlight Sys tem< 4±1> < 5±1>
See Turn Signal and
Hazard Warning
Light Sy stem< 7±3>
See ECT System< 3±5>
From Neutr al St art SW< 1±3>
See Interier Light System< 6±3> From Igniter º TACº < 1±5>
To Engine and ECT ECU< 2±7>
To Cruise Control ECU< 16±3>
To PPS ECU< 15±2> See Illumination System
<4±7><5±7>
See ECT and A/T Indic ator
Syst em< 3±6>
See Unlock and Seat Belt
Warning Syst em< 4±4> < 5±4>
W3
WATER TEMP.
SENDER
Combination Meter
1
COMBINATION METER C12 , C13 , C14
A
AB IG1
8
Under the
c ent er
pillar LH Under the
as htr ay LH
Lef t
kick panelRear side of
c ylinder head RH
C
2
G 2
F
1
F 14
L±R
P
P
SH OR T C ON NE CT OR
S2 2 G , S23 F L±R
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244
Rear Window Defogger
and Mirror Heater
Remote Control Mirror
Seat Heater
Shift Lock
SRS AIRBAG
Starting
Taillight and
Stop Light
Theft Deterrent and
Door Lock Control
Turn Signal and Hazard
Warning Light
Wiper and Washer
Wireless Door Lock
Remote Control
Horn
Ignition
Illumination
Interior Light
Liquid Crystal Inner
Rear View Mirror
Moon Roof
Power Seat
(Driver's)
Power Source
Power Window
PPS (Progressive
Power Steering
Radio and Player
ABS and
Traction Control
Automatic
Air Conditioner
Auto Antenna
Back±Up Light
Cellular Mobile
Telephone
Charging
Cigarette Lighter
Combination Meter
Cruise Control
Headlight and Light Auto
Turn Off (for USA)
Headlight
(for Canada) ECT and
A/T Indicator
4±2 16±2 7±2
3±2 21±2 3±8
14±4
18±2 19±4 (w/o CD Player)
20±8 (w/ CD Player)9±2 8±2
4±7 (for USA)
5±7 (for Canada)11±2
12±311±5 (w/ Driving
Position Memory)11±7 12±1 1±5 13±2
6±2 15±2 14±2
13±2
17±7 7±3 17±2 15±3
1±315±2
Power Tilt and
Power Telescopic12±2
Power Seat (Passengerºs
and Electric Tension Header
5±2 2±2
Cornering Light ABS (Anti±Lock
Brake System)
22±2
Engine Control Unlock and Seat
Belt Warning
1±2
23±2 (w/o Driving
Position Memory)
1 23±119±2 (w/o CD Player
20±2 (w/ CD Player
14±310±2 (w/ Memory)
5±7 (w/o Memory)
4±3 (for USA)
5±3 (for Canada) 4±5 (for USA)
5±5 (for Canada)
OVERALL ELECTRICAL WIRING DIAGRAM
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47
216182
216
178
216
129 104 144 10260
90
216 62
68
11 2
148
104
111 200 148 148 190
D1
C16 C24
C15 C19 C23 C22
C12
C13
C14C14
C13
C12
Airbag W arning Light
Charge Warning Light
Dimmer SW [Comb. SW]Cruise Control Indicator Light
[Comb. Meter]A/T Indicator Light
[Comb. Meter]
Combination Meter
Rear Lights Warning Light Turn Signal Indicator Light
[Comb. Meter] High Beam Indicator Light
[Comb. Meter]
Check Engine Warning Light
Open Door Warning Light
Traction Indicator Light
ABS Warning Light
[Comb. Meter] Seat Belt Warning LightABS Warning Light and T raction
Off Indicator Light [Comb. Meter]
Coolant Level Warning LightCruise Control ECU Turn Signal SW
[Comb. SW]
Wiper and Washer SW
[Comb. SW]
Choke Coil
Crutch Start SW
Cruise Control Clutch SW
Diode (for Brake Fluid Level)Light Control SW
[Comb. SW] Horn SW [Comb. SW]Combination MeterCornering Light SW
[Comb. SW]
C12 80
82
216
216 216 98
86
216134
216
216 216 184
216
80
90
102 80
90
102
68
94
134
148
216
(4)
: R/B No. 5 (See page ) 22
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181
THE SRS (SUPPLEMENTAL RESTRAINT SYSTEM) AIRBAG IS A DRIVER PROTECTION DEVICE WHICH HAS A SUPPLEMENTAL ROLE
TO THE SEAT BELTS.
CURRENT FLOWS CONSTANTLY TO TERMINAL 6 OF THE CENTER AIRBAG SENSOR ASSEMBLY. WHEN THE IGNITION SW IS
TURNED TO ACC OR ON, CURRENT FROM THE CIG FUSE FLOWS TO TERMINAL 14 OF THE CENTER AIRBAG SENSOR ASSEMBLY.
ONLY WHEN THE IGNITION SW IS ON DOES THE CURRENT FROM THE IGN FUSE TO TERMINAL 7 .
IF AN ACCIDENT OCCURS WHILE DRIVING, DECELERATION CAUSED BY A FRONTAL IMPACT IS DETECTED BY EACH SENSOR AND
SWITCH, AND WHEN THE FRONTAL IMPACT EXCEEDS A SET LEVEL (WHEN THE SAFING SENSOR BUILT INTO THE CENTER AIRBAG
SENSOR ASSEMBLY IS ON AND THE CENTER AIRBAG SENSOR IS ON, FRONT AIRBAG SENSORS ARE OFF), CURRENT \
FROM THE
CIG OR IGN FUSE FLOWS TO TERMINAL 11 OF THE CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 1 OF THE AIRBAG SQUIB "
SQUIB " TERMINAL 2 " TERMINAL 10 OF CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 8, TERMINAL 13 OR BODY GROUND
" GROUND.
WHEN THE SAFING SENSOR BUILT INTO THE CENTER AIRBAG SENSOR ASSEMBLY IS ON AND THE FRONT AIRBAG SENSOR LH OR
RH IS ON, CENTER AIRBAG SENSOR IS OFF AND CURRENT FROM THE CIG OR IGN FUSE FLOWS TO TERMINAL 11 OF THE CENTER
AIRBAG SENSOR ASSEMBLY " TERMINAL 1 OF THE AIRBAG SQUIB " SQUIB " TERMINAL 2 " TERMINAL 10 OF CENTER AIRBAG
SENSOR ASSEMBLY " TERMINAL 3 OR 4 " TERMINAL 1 OF FRONT AIRBAG SENSOR " TERMINAL 2 " TERMINAL 2 OR 5 OF
CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 8, TERMINAL 13 OR BODY GROUND " GROUND , WHEN THE SAFING SENSOR
BUILT INTO THE CENTER AIRBAG SENSOR ASSEMBLY IS ON, AND THE FRONT AIRBAG SENSOR LH OR RH IS ON AND CENTER
AIRBAG SENSOR IS ON ONE OF THE ABOVE±MENTIONED CIRCUITS IS ACTIVATED SO THAT CURRENT FLOWS TO THE AIRBAG
SQUIB AND CAUSES IT TO OPERATE. THE BAG STORED INSIDE THE STEERING WHEEL PAD IS INSTANTANEOUSLY EXPANDED TO
SOFTEN THE SHOCK TO THE DRIVER.
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A2928C1228T 629
C 326F 126
C1028F 226
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1E20INSTRUMENT PANEL WIRE
1G20COWL NO. 2 WIRE
1J20COWL WIRE
3A
3B
3D22INSTRUMENT PANEL WIRE
3E
3H
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IK136ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EC34FRONT SIDE OF INTAKE MANIFOLD
ED34REAR SIDE OF CYLINDER HEAD RH
IF36LEFT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
E2034ENGINE WIRE
SYSTEM OUTLINE
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