1995 TOYOTA SUPRA ignition

5. REMOVE COMBINATION SWITCH
(a) Remove the 4 screws.
(b) Disconnect the 4 connectors and airbag connector.
6. DISCONNECT INTERMEDIATE SHAFT
(a) Place matchmarks on the intermediate shaft and control
valve shaft.
(b) Loosen the bolt B and remove the bolt A.
7. REMOVE STEERING COLUMN ASSEMBLY
(a) Remove the brake pedal return spring.
(b) Loosen the hole cover clamp.
(c) Remove the 4 nuts.
STEERING COLUMN DISASSEMBLY
NOTICE: When using a vise, do not overtighten it.
1. REMOVE IGNITION KEY CYLINDER ILLUMINATION
2. REMOVE INTERMEDIATE SHAFT
Remove the bolt.
3. REMOVE SLIDING YOKE AND SHAFT THRUST
STOPPER
(a) Remove the bolt.
(b) Shift the stopper.
(c) Place matchmarks on the yoke and main shaft.
4. REMOVE COLUMN LOWER COVER
Loosen the clamp.
5. REMOVE COLUMN UPPER BRACKET
(a) U s i n g a c e n t e r i n g p u n c h , m a r k t h e c e n t e r o f t h e 2
tapered±head bolts.
(b) U s i n g a 4 ± 5 m m ( 0 .16±0.20 in.) drill, drill into the 2
tapered±head bolts.
(c) Using a screw extractor, remove the 2 tapered±head bolts.
(d) Remove the bracket and column upper clamp.
6. REMOVE WIRING HARNESS CLAMP AND COLUMN
PROTECTOR
7. REMOVE COMPRESSION SPRING
(a) Using a torx socket wrench, remove the screw.
(b) Remove the 2 bushings from the spring.
8. REMOVE 3 TENSION SPRINGS
9. REMOVE TURN SIGNAL BRACKET
Remove the 2 bolts.
± STEERINGTILT STEERING COLUMNSR±15

STEERING COLUMN INSPECTION AND
REPLACEMENT
1. INSPECT KEY CYLINDER
Check that the steering lock mechanism operates properly.
2. IF NECESSARY, REPLACE KEY CYLINDER
(a) Place the ignition key at the ACC position.
(b) Push down the stop pin with a screwdriver and pull out the
key cylinder.
(c) Install a new cylinder.
HINT: Make sure the ignition key is at the ACC position.
3. IF NECESSARY, REPLACE UNLOCK WARNING SWITCH
AND IGNITION SWITCH
(a) Remove the 2 screws and warning switch.
(b) Remove the 2 screws and ignition switch.
(c) Install a new ignition switch with the 2 screws.
(d) Install a new warning switch with the 2 screws.
4. A/T:
INSPECT KEY INTER LOCK SOLENOID
(See page AT1±30)
5. A/T:
IF NECESSARY, REPLACE KEY INTERLOCK SOLENOID
(a) Remove the 2 screws and solenoid.
(b) Install a new solenoid with the 2 screws.
6. IF NECESSARY, REPLACE MAIN SHAFT BUSHING
(a) Using a screwdriver, depress the 3 projections on the busing
to release the bushing, then remove the bushing.
NOTICE: If the bushing interior is worn, install a new
bushing.
(b) Align the projections on a new bushing with the holes in the
lower tube. Install the bushing until the projections are firmly
engaged in the holes in the lower tube.
STEERING COLUMN ASSEMBLY
NOTICE: When using a vise, do not overtighten it.
1. APPLY MOLYBDENUM DISULPHIDE LITHIUM BASE
GREASE (See page SR±13)
2. INSTALL MAIN SHAFT BUSHING STOPPER AND MAIN
SHAFT COLLAR
± STEERINGTILT STEERING COLUMNSR±17

ELECTRONIC CONTROL SYSTEM
TROUBLESHOOTING FLOW±CHART
Trouble Symptom
wHard steering at idle or low±speed driving.
wSteering too sensitive during high±speed driving.
Preliminary Check
wCheck tire pressure.
wCheck lubrication of suspension and steering linkage.
wCheck front wheel alignment.
wCheck steering system joint and suspension arm ball joint.
wCheck for bent steering column.
wCheck that all connectors are secure.
wCheck PS pump fluid pressure. (See page SR±37)
Turn ignition switch on.
Is ECU±IG fuse normal?
Disconnect the ECU connector.
Fuse faulty.
Replace fuse.
Is operation normal?Short circuit in wire
harness between fuse
and ECU terminal +B.
Check 1.
Check that there is battery voltage (10 Ð 14V) between the
ECU terminal +B and body ground.
Open circuit in wire harness between the fuse and ECU terminal +B.
± STEERINGELECTRONIC CONTROL SYSTEMSR±47

GENERAL DESCRIPTION
The SUPRA is equipped with an SRS (Supplemental Restraint System), which comprises a driver
airbag, and front passenger airbag if fitted. Failure to carry out service operations in the correct
sequence could cause the SRS to unexpectedly deploy during servicing, possibly leading to a seri-
ous accident. Further, if a mistake is made in servicing the SRS, it is possible the SRS may fail to
operate when required. Before performing servicing (including removal or installation of parts, in-
spection or replacement), be sure to read the following items carefully, then follow the correct pro-
cedure described in the repair manual.
1. Malfunction symptoms of the SRS are difficult to confirm, so the diagnostic trouble codes become the most
important source of information when troubleshooting. When troubleshooting the SRS, always inspect the
diagnostic trouble codes before disconnecting the battery.
(See page RS±44)
2. Work must be started after 90 seconds from the time the ignition switch is turned to the ºLOCKº
position and the negative (±) terminal cable is disconnected from the battery.
(The SRS is equipped with a back±up power source so that if work is started within 90 seconds of
disconnecting the negative (±) terminal cable from the battery, the SRS may deploy.)
When the negative (±) terminal cable is disconnected from the battery, memory of the clock and audio sys-
tems will be canceled. So before starting work, make a record of the contents memorized by the audio
memory system. When work is finished, reset the audio systems 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.
3. Even in cases of a minor collision where the SRS does not deploy, the steering wheel pad, front passenger
airbag assembly, front airbag sensors and center airbag sensor assembly should be inspected.
(See pages RS±10, 20, 30, and 33)
4. Never use SRS parts from another vehicle. When replacing parts, replace them with new parts.
5. Before repairs, remove the airbag sensors if shocks are likely to be applied to the sensors during repairs.
6. Never disassemble and repair the steering wheel pad, front passenger airbag assembly, front airbag
sensors or center airbag sensor assembly in order to reuse it.
7. If the steering wheel pad, front passenger airbag assembly, front airbag sensors or center airbag sensor
assembly have been dropped, or if there are cracks, dents or other defects in the case, bracket or
connector, replace them with new ones.
8. Do not expose the steering wheel pad, front passenger airbag assembly, front airbag sensors or center
airbag sensor assembly directly to hot air or flames.
9. Use a volt/ohmmeter with high impedance (10 k
/V minimum) for troubleshooting the system's electrical
circuits.
10. Information labels are attached to the periphery of the SRS components. Follow the instructions on the
notices.
11. After work on the SRS is completed, check the SRS warning light.
(See page RS±44)
12. If the vehicle is equipped with a mobile communication system, refer to the precaution in the IN section. RS±2
± SUPPLEMENTAL RESTRAINT SYSTEMGENERAL DESCRIPTION

OPERATION
FUNCTION OF COMPONENTS
1. STEERING WHEEL PAD (with AIRBAG)
The inflater and bag of the SRS are stored in the steering
wheel pad and cannot be disassembled. The inflater con-
tains a squib, igniter charge, gas generant, etc., and inflates
the bag when instructed by the center airbag sensor assem-
bly.
2. SPIRAL CABLE (in COMBINATION SWITCH)
A spiral cable is used as an electrical joint from the vehicle
body side to the steering wheel.
3. FRONT PASSENGER AIRBAG ASSEMBLY
The inflater and bag of the SRS are stored in the front pas-
senger airbag assembly and cannot be disassembled.
The inflater contains a squib, igniter charge, gas generant,
etc., and inflates the bag when instructed by the center airbag
sensor assembly.
4. SRS WARNING LIGHT
The SRS warning light is located on the cluster finish panel.
It goes on to alert the driver of trouble in the system when a
malfunction is detected in the center airbag sensor assembly.
In normal operating conditions when the ignition switch is
turned to the ACC or ON position, the light goes on for about
6 seconds and then goes off.
5. FRONT AIRBAG SENSOR
A front airbag sensor is mounted inside each of the front fend-
ers. The sensor unit is a mechanical type. When the sensor
detects a deceleration force above a predetermined limit,
contacts is made in the sensor, sending a signal to the center
airbag sensor assembly. The sensor cannot be disas-
sembled. RS±4
± SUPPLEMENTAL RESTRAINT SYSTEMOPERATION

6. CENTER AIRBAG SENSOR ASSEMBLY
The center airbag sensor assembly is mounted on the floor
inside the console box. The center airbag sensor assembly
consists of a center airbag sensor, safing sensor, diagnosis
circuit and ignition control, drive circuit, etc. It receives signals
from the airbag sensors and judges whether the SRS must
be activated or not.
7. SRS CONNECTORS
 No. Item Application 
 (1)
 
  Terminal Twin±Lock Mechanism
 
  Connectors (1), (2), (3), (4), (5), (6), (7)
 (2)  Airbag Activation Prevention Mechanism  Connectors (1), (4), (5), (6)
 (3)  Electrical Connection Check Mechanism  Connectors (1), (2), (3)
 (4)  Connector Twin±Lock Mechanism  Connectors (4), (5), (6)
All connectors in the SRS are colored yellow to distinguish
them from other connectors. Connectors having special func-
tions and specifically designed for SRS are used in the loca-
tions shown below to ensure high reliability. These connec-
tors use durable gold±plated terminals.
± SUPPLEMENTAL RESTRAINT SYSTEMOPERATIONRS±5

When the vehicle is involved in a frontal collision in the
hatched area (Fig. 1) and the shock is larger than a predeter-
mined level, the SRS is activated automatically. A safing sen-
sor is designed to go on at a smaller deceleration rate than
the front and center airbag sensors. As illustrated in Fig. 2,
ignition is caused when current flows to the squib, which hap-
pens when a safing sensor and a front airbag sensor and/or
the center airbag sensor go on simultaneously. When a de-
celeration force acts on the sensors, two squibs in the driver
airbag and front passenger airbag ignite and generate gas.
The gas discharging into the driver and front passenger air-
bags rapidly increases the pressure inside the bags, break-
ing open the steering wheel pad and instrument panel door.
Bag inflation then ends, and the bags deflate as the gas is
discharged through discharge holes at the bag's rear or side. RS±8
± SUPPLEMENTAL RESTRAINT SYSTEMOPERATION

4. DISPOSAL OF STEERING WHEEL PAD (WITH AIRBAG)
CAUTION:
wThe steering wheel pad is very hot when the airbag is
deployed, so leave it alone for at least 30 minutes after
deployment.
wUse gloves and safety glasses when handling a steering
wheel pad with a deployed airbag.
wDo not apply water, etc. to a steering wheel pad with a
deployed airbag.
wAlways wash your hands with water after completing the
operation.
(a) When scrapping a vehicle, deploy the airbag and scrap the
vehicle with the steering wheel pad still installed.
(b) When moving a vehicle for scrapping which has a steering
wheel pad with deployed airbag, use gloves and safety
glasses.
When disposing of steering wheel pad only
When disposing of the steering wheel pad (with airbag)
only, never use the customer's vehicle to deploy the air-
bag.
Remove the steering wheel pad from the vehicle and be sure
to follow the procedure given below when deploying the air-
bag.
HINT: Have a battery ready as the power source to deploy the
airbag.
1. REMOVE STEERING WHEEL PAD (See SR section)
CAUTION:
wWhen removing the steering wheel pad (with airbag),
work must be started after 90 seconds from the time the
ignition switch is turned to the ºLOCKº position and the
negative (±) terminal cable is disconnected from the
battery.
wWhen storing the steering wheel pad, keep the upper
surface of the pad facing upward.
2. REMOVE STEERING WHEEL PAD CONNECTOR
Remove the connector on the steering wheel pad rear sur-
face from the inflater cover.
± SUPPLEMENTAL RESTRAINT SYSTEMSTEERING WHEEL PAD AND SPIRAL CABLERS±15