1986 TOYOTA SUPRA Service Repair Manual

195
CURRENT ALWAYS FLOWS TO TERMINAL 1 OF THE INTEGRATION RELAY THROUGH DOME FUSE.
1.SEAT BELT WARNING SYSTEM
WHEN THE IGNITION SW IS TURNED ON, CURRENT FLOWS FROM THE GAUGE FUSE TO TERMINAL 7 OF THE INTEGRATION RELAY.
AT THE SAME TIME, CURRENT FLOWS TO TERMINAL 9 OF THE RELAY FROM THE GAUGE FUSE THROUGH THE SEAT BELT
WARNING LIGHT. THIS CURRENT ACTIVATES THE INTEGRATION RELAY AND CURRENT FLOWING THROUGH THE WARNING LIGHT
FLOWS FROM TERMINAL 9 OF THE RELAY " TERMINAL 10 " GROUND, CAUSING THE WARNING LIGHT TO LIGHT UP. A BUCKLE SW
OFF SIGNAL IS INPUT TO TERMINAL 8 OF THE RELAY, THE CURRENT FLOWING TO TERMINAL 7 OF THE RELAY FLOWS THROUGH
TERMINAL 10 " GROUND AND THE SEAT BELT WARNING BUZZER SOUNDS FOR APPROX. 4±8 SECONDS. HOWEVER, IF THE SEAT
BELT IS PUT ON DURING THIS PERIOD (WHILE THE BUZZER IS SOUNDING), SIGNAL INPUT TO TERMINAL 8 OF RELAY STOPS AND
THE CURRENT FLOW FROM TERMINAL 7 OF THE RELAY " TERMINAL 10 " GROUND IS CUT, CAUSING THE BUZZER TO STOP.
2. UNLOCK WARNING SYSTEM
WITH THE IGNITION KEY INSERTED IN THE KEY CYLINDER (UNLOCK SW ON), THE IGNITION SW STILL OFF AND DRIVER'S DOOR
OPENS (DOOR COURTESY SW ON), WHEN A SIGNAL IS INPUT TO TERMINAL 6 OF THE RELAY, THE INTEGRATION RELAY
OPERATES, CURRENT FLOWS FROM TERMINAL 7 OF THE RELAY " TERMINAL 10 " GROUND AND UNLOCK WARNING BUZZER
SOUNDS.
B 6 BUCKLE SW LH
1±2 : CLOSED WITH DRIVER'S SEAT BELT IN USE
D10 DOOR COURTESY SW LH
3±2 : CLOSED WITH LH DOOR OPEN
U 1 UNLOCK WARNING SW
2±1 : CLOSED WITH IGNITION KEY IN CYLINDER
INTEGRATION RELAY
10±GROUND : ALWAYS CONTINUOUS
6±GROUND : CONTINUOUS WITH DRIVER'S DOOR OPEN
5±GROUND : CONTINUOUS WITH IGNITION KEY IN CYLINDER
8±GROUND : CONTINUOUS WITH DRIVER'S SEAT BELT IN USE
9±GROUND :0 VOLTS WITH IGNITION SW ON AND BUCKLE SW OFF
1±GROUND : ALWAYS APPROX. 12 VOLTS
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
B 628T 629
D1030U 129
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
222R/B NO. 2 (ENGINE COMPARTMENT LEFT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE AND J/B NO. 1 (LEFT KICK PANEL)
1C20FLOOR NO. 2 WIRE AND J/B NO. 1 (LEFT KICK PANEL)
1E20INSTRUMENT PANEL WIRE AND J/B NO. 1 (LEFT KICK PANEL)
1I
1J20COWL WIRE AND J/B NO. 1 (LEFT KICK PANEL)
1K
20COWL WIRE AND J/B NO. 1 (LEFT KICK PANEL)
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IC236FLOOR NO. 2 WIRE AND COWL WIRE (LEFT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IE36LEFT KICK PANEL
BI40LEFT QUARTER PILLAR
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I 738FLOOR NO. 2 WIRE
SYSTEM OUTLINE
SERVICE HINTS

196
UNLOCK AND SEAT BELT WARNING

197
SRS (SUPPLEMENTAL RESTRAINT SYSTEM)
NOTICE: When inspecting or repairing the SRS (supplemental restraint system), perform the operation in
accordance with the following precautionary instructions and the procedure and precautions in the Repair
Manual for the applicable model year.

Malfunction symptoms of the supplemental restraint system are difficult to confirm, so the diagnostic trouble
codes become the most important source of information when troubleshooting.
When troubleshooting the supplemental restraint system, always inspect the diagnostic trouble codes before
disconnecting the battery.

Work must be started after 90 seconds from the time the Ignition SW is set to the ªLOCKº position and the
negative (±) terminal cable is disconnected from the battery.
(The supplemental restraint system is equipped with a back±up power source so that if work is started within
90 seconds of disconnecting the negative (±) terminal cable of the battery, the SRS may be activated.)
When the negative (±) terminal cable is disconnected from the battery, memory of the clock and audio systems
will be cancelled. So before starting work, make a record of the contents memorized by each memory system.
When work is finished, reset the clock and audio system as before and adjust the clock.
To avoid erasing the memory of each memory system, never use a back±up power supply from outside the
vehicle.

When removing the steering wheel pad or handling a new steering wheel pad, keep the pad upper surface
facing upward. Also, lock the lock lever of the twin lock type connector at the rear of the pad and take care
not to damage the connector.
(Storing the pad with its metallic surface up may lead to a serious accident if the SRS inflates for some reason.)

Always store a removed or new front passenger airbag assembly with the airbag door facing up. Storing the
airbag assembly with the airbag door facing down could cause a serious accident if the airbag inflates.

Store the steering wheel pad where the ambient temperature remains below 93°C (200°F), without high
humidity and away from electrical noise.

Never use SRS parts from another vehicle. When replacing SRS parts, replace them with new parts.

Never disassemble and repair the steering wheel pad, front passenger airbag assembly, center airbag sensor
assembly or front airbag sensors.

Before repairing the body, remove the airbag sensors if during repair shocks are likely to be applied to the
sensors due to vibration of the body or direct tapping with tools or other parts.

Do not reuse a steering wheel pad or front airbag sensors.
After evaluating whether the center airbag sensor assembly is damaged or not, decide whether or not to reuse
it. (See the Repair Manual for the method for evaluating the center airbag sensor assembly.)

When troubleshooting the supplemental restraint system, use a high±impedance (Min. 10k
/V) tester.

The wire harness of the supplemental restraint system is integrated with the cowl No. 2 wire harness
assembly.
The vehicle wiring harness exclusively for the airbag system is distinguished by corrugated yellow tubing, as
are the connectors.

Do not measure the resistance of the airbag squibs.
(It is possible this will deploy the airbag and is very dangerous.)

If the wire harness used in the supplemental restraint system is damaged, replace the whole wire harness
assembly.
When the connector to the front airbag sensors can be repaired alone (when there is no damage to the wire
harness), use the repair wire specially designed for the purpose.
(Refer to the Repair Manual for the applicable Model year for details of the replacement method.)

INFORMATION LABELS (NOTICES) are attached to the periphery of the SRS components. Follow the
instructions on the notices.

198
SRS (SUPPLEMENTAL RESTRAINT SYSTEM)
The supplemental restraint system has connectors which possess the functions described below:
1. SRS ACTIVATION PREVENTION MECHANISM
Each connector contains a short spring plate. When the
connector is disconnected, the short spring plate
automatically connects the power source and grounding
terminals of the squib to preclude a potential difference
between the terminals.
2. ELECTRICAL CONNECTION CHECK MECHANISM
This mechanism is designed to electrically check if
connectors are connected correctly and completely.
The electrical connection check mechanism is designed so
that the connection detection pin connects with the
diagnosis terminals when the connector housing lock is in
the locked condition.

199
3. CONNECTOR TWIN±LOCK MECHANISM
With this mechanism connectors (male and female
connectors) are locked by two locking devices to increase
connection reliability. If the primary lock is incomplete, ribs
interfere and prevent the secondary lock.

200
SRS (SUPPLEMENTAL RESTRAINT SYSTEM)
7. 5A
IGN15A
CIG10A
ECU±B
1G 10 1G61E13
152
II1 12 II121 IF12IF111
I14
I14 I 5
1E3 1E4
1G7 1G9
13 14 12 7
8 9 11 10 34 21 56+SL ±SL +SR ±SR D+ D± P+ P± E1 E2AB TC AB TC
511 12 4
P±B B±Y B±Y
P±B
B±O
L±R
B±Y W±R
B±Y
P±B
B±Y
P±B B±Y
P±B
B±Y
P±B B±Y
P±B
S RS WARNING
LIGHT
[TELLTALE
LIGHT RH] T6DA TA LINK
CONNECTOR 1
(
CHECK CONNE CTOR)DATA LINK
CONNECTOR 2
(
TDCL) D1 D5 FROM POWER SOURCE SYSTEM(
SEE PAGE 56)
1G 31G4
1J 1
IE 12
12 12
12
F1 F2
A2 7 A2 8 IG2 ACC LA TC
FRONT AIRBAG
SENSOR LHFRONT AIRBAG
SENSOR RH
AIRBAG SQUIB
(
STE ERING WHE EL
PAD)AIRBAG SQUIB
(
FRONT PASSENGER
AIRBAG ASSEMBLY) CENTER AIRBAG SENSOR ASSEMBLY
W±BR
W
GR
B
Y
L
G
BR
W±B
W±B
C5
SPIRAL
CABLE AABB (
*1)(
*1)* 1 : CONNECTION DETECTION PIN

201
*THE SRS (SUPPLEMENTAL RESTRAINT SYSTEM) IS A DRIVER AND FRONT PASSENGER PROTECTION DEVICE WHICH HAS A
SUPPLEMENTAL ROLE TO THE SEAT BELTS.
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, THE CURRENT FLOWS FROM THE IGN FUSE TO TERMINAL 13.
IF AN ACCIDENT OCCURS WHILE DRIVING, WHEN DECELERATION CAUSED BY A FRONTAL IMPACT IS DETECTED BY EACH SENSOR
AND SWITCH, AND 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 TERMINALS 3, 2, OF THE CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 1 OF THE AIRBAG SQUIB
" TERMINAL 2 " TERMINALS 4, 1, OF THE CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 5, TERMINAL 6 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 TERMINALS 3, 2, OF THE
CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 1 OF THE AIRBAG SQUIB " TERMINAL 2 " TERMINALS 4, 1, OF THE CENTER
AIRBAG SENSOR ASSEMBLY " TERMINAL 8 OR 11 " TERMINAL 1 OF THE FRONT AIRBAG SENSOR " TERMINAL 2 " TERMINAL 9
OR 10 OF THE CENTER AIRBAG SENSOR ASSEMBLY " TERMINAL 5, TERMINAL 6 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 SQUIBS AND CAUSES THEN TO OPERATE.
THE AIRBAG STORED INSIDE THE STEERING WHEEL PAD IS INSTANTANEOUSLY EXPANDED TO SOFTEN THE SHOCK TO THE
DRIVER.
THE AIRBAG STORED INSIDE THE PASSENGER'S INSTRUMENT PANEL IS INSTANTANEOUSLY EXPANDED TO SOFTEN THE SHOCK
TO THE PASSENGER.
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A2728D 126 (2JZ±GE)F224 (2JZ±GTE)
A2828D 528F 226 (2JZ±GE)
C 528F124 (2JZ±GTE)T 629
D 124 (2JZ±GTE)F 126 (2JZ±GE)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1E20INSTRUMENT PANEL WIRE AND J/B NO. 1 (LEFT KICK PANEL)
1G20COWL WIRE AND J/B NO 1 (LEFT KICK PANEL)1J20COWL WIRE AND J/B NO. 1 (LEFT KICK PANEL)
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IF136INSTRUMENT PANEL WIRE AND COWL WIRE (INSTRUMENT PANEL REINFORCEMENT LH)
II138ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IE36LEFT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I 538INSTRUMENT PANEL WIREI1438INSTRUMENT PANEL WIRE
SYSTEM OUTLINE

202
SRS (SUPPLEMENTAL RESTRAINT SYSTEM)