sensor LEXUS SC400 1991 Service Repair Manual

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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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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OKNG
YESNO
YESNO
4Check SRS warning light circuit.
C
OK
P1. Disconnect center airbag sensor assembly.
2. Connect negative (±) terminal cable to battery.
3. Turn ignition switch ACC or ON.
Measure voltage LA terminal of harness side connector
of center airbag sensor assembly.
Voltage: Battery positive voltage.
Repair SRS warning light circuit.
5Does SRS warning light come on?
C
OK
P1. Disconnect negative (±) terminal cable from bat-tery.
2. Connect center airbag sensor assembly.
3. Connect negative (±) terminal cable to battery.
4. Turn ignition switch ACC or ON.
Check operation of SRS warning light.
SRS warning light comes on.
Check terminal LA of center airbag sensor assembly and
electrical connection check mechanism. If normal, re-
place 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.
6Is new ECU±B fuse burnt out again?
Using simulation method, reproduce malfunction symp-
toms (See page RS±65).
Check harness between ECU±B fuse and SRS warning light, and ECU±B fuse a\
nd center airbag sensor
assembly.
RS±106±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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YESNo
HINT: If diagnostic trouble code 22 is output, perform the following troubles\
hooting:
1Is diagnostic trouble code 22 output again?
C
PClear malfunction.
1. Turn ignition switch LOCK, and wait at least 20 sec-onds.
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.
Using simulation method, reproduce malfunction symp-
toms (See page RS±65).
Replace center airbag sensor assembly.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±107
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DTC31Center Airbag Sensor Assembly Malfunction
CIRCUIT DESCRIPTION
The center airbag sensor assembly consists of center airbag sensor, safing sensors, ignition control and drive
circuit, diagnosis circuit, etc.
It receives signals from the airbag sensors, judges whether or not the SRS must be deploy, and diagnoses sys-
tem malfunction.
Diagnostic trouble code 31 is recorded when occurrence of a malfunction in the cen\
ter airbag assembly is de-
tected.
DTC No.Trouble Area
31
Center airbag sensor assembly malfunction.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
HINT: When a malfunction code other than code 31 is displayed at the same time, first repair the malfunction
indicated by the malfunction code other than code 31.
(See page RS±65).
RS±108±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTING
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YESNO
INSPECTION PROCEDURE
HINT: When a malfunction code other than code 31 is displayed at the same time, first repair the malfunction
indicated by the malfunction code other than 31.
1Is diagnostic rouble code 31 output again?
C
PClear malfunction.
1. Turn ignition switch LOCK, and wait at least 20 sec-onds.
2. Turn ignition switch ACC or ON, and wait at least 20 seconds.
3. Repeat operation in step (1) and (2) at least 5 times.
4. Using SST, connect terminals Tc and E
1 of DLC2.
SST 09843±18020
5. Check diagnostic trouble code.
Using simulation method, reproduce malfunction symp-
toms (See page RS±65).
Replace center airbag sensor assembly.
±
SUPPLEMENTAL RESTRAINT SYSTEM TROUBLESHOOTINGRS±109
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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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STEERING KNUCKLE WITH AXLE HUB
REMOVAL
SA01Y±08
1. JACK UP VEHICLE AND REMOVE FRONT WHEEL
2. REMOVE FRONT BRAKE CALIPER AND BRAKE DISC
(a) Remove the 2 bolts and remove the brake caliper from thesteering knuckle.
(b) Hang up the brake caliper using wire, etc.
(c) Place matchmarks on the brake disc and axle hub.
(d) Remove the 2 screws and remove the brake disc.
3. REMOVE ABS SPEED SENSOR FROM STEERING KNUCKLE
Remove the bolt and disconnect the sensor from the steering
knuckle.
4. CHECK BACKLASH IN BEARING SHAFT DIRECTION Place the dial indicator near the center of the axle hub and
check the backlash in the bearing shaft direction.
Maximum:
0.05 mm (0.0020 in.)
If greater than the specified maximum, replace the bearing.
±
SUSPENSION AND AXLE FRONT AXLE HUBSA±17
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FRONT AXLE HUB DISASSEMBLY
SA0RL±04
1. REMOVE HUB BEARING CAPUsing a screwdriver, remove the hub bearing cap from the
steering knuckle.
2. REMOVE FRONT AXLE HUB LOCK NUT AND ABS SPEED SENSOR ROTOR
(a) Clamp the axle hub in a soft jaw vise.
HINT: Close vise until it holds hub bolt do not tighten further.
(b) Using a hammer and chisel, loosen the staked part of the lock
nut and remove it.
(c) Remove the sensor rotor.
NOTICE: Take care not to scratch the serrations of the sensor
rotor.
3. REMOVE AXLE SHAFT FROM STEERING KNUCKLE
(a) Remove the 4 bolts and shift the brake dust cover toward the hub side (outside).
(b) Using SST, remove the axle shaft from the steering knuckle. SST 09950±20017
±
SUSPENSION AND AXLE FRONT AXLE HUBSA±19
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(b) Using SST and a press, press the axle hub to steeringknuckle.
SST 09608±32010, 09608±35014 (09608±06040)
4. INSTALL ABS SPEED SENSOR ROTOR NOTICE: Do not scratch the serrations of the sensor ro-
tor.
5. INSTALL AXLE HUB LOCK NUT
(a) Install and torque a new axle hub lock nut.
Torque: 199 N Vm (2,030 kgf Vcm, 147 ft Vlbf)
(b) Using a screwdriver and hammer, stake the lock nut.
6. INSTALL HUB BEARING CAP
Using a screwdriver and hammer, install the hub bearing cap
to the steering knuckle.
SA±22
±
SUSPENSION AND AXLE FRONT AXLE HUB
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