1991 LEXUS SC400 steering

NGOK
INSPECTION PROCEDURE
1Preparation.
P1. Disconnect battery negative (±) terminal cable, andwait at least 90 seconds.
2. Remove steering wheel pad. (See page RS±19)
3. Disconnect connectors of front passenger airbag assembly (See page RS±32).
Caution: Store the steering wheel pad with the
surface facing upward.
2Check D squib circuit.
C
OK
PDisconnect center airbag sensor assembly connector.
Measure resistance between D+ and D± on spiral cable
side of connector between spiral cable and steering
wheel pad.
Resistance: Below 1

Go to Step
.
RS±94
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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OKNG
OKNG
3Check spiral cable.
C
OK
PDisconnect connector between center airbag sensor
assembly and spiral cable.
Measure resistance between D
+ and D± on spiral cable
side of connector between spiral cable and steering
wheel pad.
Resistance: Below 1

Repair or replace spiral cable.
4Check harness between center airbag sensor assembly and spiral cable.
C
OK
Measure resistance between D+ and D± on center air-
bag sensor assembly side of connector between center
airbag sensor assembly and spiral cable.
Resistance: Below 1

Repair or replace harness or connector between center
airbag sensor assembly and spiral cable.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±95
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OKNG
OKNG
5Check center airbag sensor assembly.
C
OK
Hint
P1. Connect connector to center airbag sensor connec-
tor.
2. Connect connector between center airbag sensor assembly and spiral cable.
3. Using a service, wire, connect D
+ and D±. P+ and
P±.
4. Connect negative (±) terminal cable to battery and wait at least 2 second.
1. turn ignition switch ACC or ON, and wait at least 20
seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
2. Turn ignition switch ACC or ON, and wait at least 20
seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
4. Check diagnostic trouble code.
Diagnostic trouble code 14 is not output.
Codes other than code 14 may be output at this time ,
but this is not relevant to this check.
Replace center airbag sensor assembly.
6Check D squib.
C
OK
Hint
P1. Turn ignition switch LOCK.
2. Disconnect battery negative (±) terminal cable, and wait at least 90 seconds.
3. Connect steering wheel pad (squib) connector.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch ACC or ON, and wait at least 20
seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
2. Turn ignition switch ACC or ON, and wait at least 20
seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
4. Check diagnostic trouble code.
Diagnostic trouble code 14 is not output.
Codes other t han code 14 may be output at this time, but
this is not relevant to this check.
Replace steering wheel pad.
From the results of the above inspection, the malfunctioning part can now be\
considered normal. To
make sure of this, use the simulation method to check.
RS±96±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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OKNG
INSPECTION PROCEDURE
1Preparation.
P1. Disconnect battery negative (±) terminal cable, andwait at least 90 seconds.
2. Remove steering wheel pad (See page RS±19).
3. Disconnect connectors of front passenger airbag assembly (See page RS±32).
Caution: Store the steering wheel pad with the
surface facing upward.
2Check front airbag sensor circuit (Measure resistance between terminals +SR \
and ±SR, +SL
and ±SL of center airbag sensor assembly connector.)
C
OK
PDisconnect center airbag sensor assembly connector.
Measure resistance between terminals +SR and ±SR,
+SL and ±SL of harness side connector of center airbag
sensor assembly.
Resistance: 755
± 885

Go to step
.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±99
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OKNG
3Check center airbag sensor assembly.
C
OK
Hint
P1. Connect connector to center airbag sensor assem-bly.
2. Using a service wire, connect D+ and D± on spiral cable side of connector between spiral cable and
steering wheel pad.
3. Using a service wire, connect P+ and P±n on center
airbag sensor assembly side of connector between
center airbag sensor assembly and front passen-
ger airbag.
4. Connect negative (±) terminal cable to battery, and wait at least 2 seconds.
1. Turn ignition switch AAC or ON, and wait at least 20 seconds.
Clear malfunction code. Turn ignition switch LOCK
and wait at least 20 seconds.
2. Turn ignition switch ACC or ON, and wait at least 20
seconds.
3. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
4. Check diagnostic trouble code.
Diagnostic trouble code 15 is not output.
Code other than code 15 may be output at this time, but
this is not relevant to this check.
Replace center airbag sensor assembly.
From the results of the above inspection, the malfunctioning part can now be\
considered normal. To
make sure of this, use the simulation method to check.
RS±100±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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OKNG
OKNG
INSPECTION PROCEDURE
HINT: If SRS warning light does not light up, perform the following troublesh\
ooting:
1Check ECU±B fuse.
Go to step

2Preparation.
P1. Disconnect battery negative (±) terminal cable, and
wait at least 90 seconds.
2. Remove steering wheel pad (See page RS±19).
3. Disconnect connectors of front passenger airbag assembly (See page RS±32).
Caution: Store the steering wheel pad with the
surface facing upward.
3Check connection of center airbag sensor assembly connector.
Repair.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±105
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TORQUE SPECIFICATIONS
SA0WG±03
(FRONT)
\
 \
Part tightened NVm kgf Vcm ft Vlbf
\
 \
Hub nut 103 1,050 76
\
 \
Front and rear adjusting cam bolt 226 2,300 166
\
 \
Axle hub lock nut 199 2,030 147
\
 \
Lower ball joint X Steering knuckle 125 1,270 92
\
 \
Tie rod end X Steering knuckle 49 500 36
\
 \
Steering knuckle X Upper suspension arm 103 1,050 76
\
 \
Lower ball foint X Lower suspension arm 127 1,300 94
\
 \
Disc brake caliper X Steering knuckle 11 8 1,200 87
\
 \
Speed sensor set bolt 103 80 76 in. Vlbf
\
 \
Front shock absorber X Body 35 360 26
\
 \
Front shock absorber X Lower suspension arm 143 1,460 106
\
 \
Upper suspension arm mounting nut 164 1,670 121
\
 \
Piston rod lock nut 29 300 22
\
 \
Stabilizer link X Lower suspension arm 74 750 54
\
 \
Stabilizer link X Stabilizer bar 74 750 54
\
 \
Stabilizer bar bracket X Body 18 180 13
\
 \
Steering knuckle X Disc brake dust cover 19 195 14
(REAR)
\
 \
Part tightened N Vm kgf Vcm ft Vlbf
\
 \
Shock absorber X Lower suspension arm 143 1,460 106\
 \
Upper arm X Body 164 1,670 271\
 \
Rear axle carrier X Brake caliper 104 1,065 77\
 \
No. 1 lower arm X Rear axle carrier 59 600 43\
 \
No. 1 lower arm X Body 184 1,880 136
\
 \
No. 2 lower arm X Rear axle carrier 150 1,525 11 0
\
 \
No. 2 lower arm X Body 184 1,880 136
\
 \
Strut rod X Rear axle carrier 184 1,880 136
\
 \
Strut rod X Body 184 1,880 136
\
 \
Rear drive shaft X Axle hub 289 2,950 213
\
 \
Upper ball joint X Rear axle carrier 109 1,110 80
\
Parking brake backing plate X Rear axle carrier2626019\
 \
Rear drive shaft X Differential 83 850 64\
 
\

\
Differential mounting bolt \
Front
Rear 

147
142 

1,500
1,450 

108
105
\
 \
Differential carrier cover set bolt 47 475 34
\
 \
Suspension support X Body 27 280 20
\
 \
Suspension support X Shock absorber rod 27 280 20
\
 \
Stabilizer bar link nut 74 750 54
\
 \
Stabilizer bar bushing retainer bolt 28 290 21
±
SUSPENSION AND AXLE SERVICE SPECIFICATIONSSA±129
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4. CHECK WHEEL BEARING LOOSENESS
(a) Check the backlash in bearing shaft direction.
Maximum: 0.05 mm (0.0020 in.)
(b) Check the axle hub deviation.
Maximum: 0.05 mm (0.0020 in.)
5. CHECK FRONT SUSPENSION FOR LOOSENESS
6. CHECK STEERING LINKAGE FOR LOOSENESS
7. CHECK BALL JOINT FOR EXCESSIVE LOOSENESS
8. CHECK SHOCK ABSORBER WORK PROPERLYwCheck for oil leak
w Check mounting busings for wear
w Bounce front and rear of the vehicle
SA±4
±
SUSPENSION AND AXLE GENERAL INSPECTION
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