1991 LEXUS SC400 engine

STABILIZER BAR AND LINK REMOVAL
SA0WH±02
1. JACK UP VEHICLE AND REMOVE FRONT WHEELS
2. REMOVE ENGINE UNDER COVER
3. REMOVE BOTH SIDE STABILIZER BAR LINKSRemove the nuts and the stabilizer bar links from the stabiliz-
er bar and the lower suspension arm.
4. REMOVE STABILIZER BAR Remove the 4 bracket mounting bolts and the stabilizer bar
with the cushions and brackets.
5. REMOVE CUSHIONS AND BRACKETS
STABILIZER BAR LINK INSPECTION
SA035±0C
INSPECT BALL JOINT FOR ROTATION CONDITION
(a) As shown, flip the ball joint stud back and forth 5 times, before
installing the nut.
(b) Using a torque wrench, turn the stud continuously one turn every 2±4 seconds and take the torque reading on the 5th
turn.
Torque (turning):
0.05 ± 1.5 N Vm (0.5 ± 15 kgf Vcm, 0.4 ± 13 in. Vlbf)
STABILIZER BAR AND LINK
INSTALLATION
SA0WJ±02
1. INSTALL CUSHIONS AND BRACKETS
(a) Install the cushion so as to touch the line painted on the
stabilizer bar.
HINT: Install the cushion to the inside of the line.
(b) Install the brackets.
SA±46
±
SUSPENSION AND AXLE FRONT SUSPENSION
WhereEverybodyKnowsYourName

2. INSTALL STABILIZER BARInstall the stabilizer bar to the body with the bolts.
Torque: 18 N Vm (180 kgf Vcm, 13 ft Vlbf)
3. INSTALL BOTH SIDE STABILIZER BAR LINKS
Install the stabilizer bar links to the stabilizer bar and the low-
er suspension arm with the nuts.
Torque: 74 N Vm (750 kgf Vcm, 54 ft Vlbf)
4. REMOVE ENGINE UNDER COVER
5. INSTALL FRONT WHEEL AND LOWER VEHICLE
Torque: 103 N Vm (1,050 kgf Vcm, 76 ft Vlbf)
±
SUSPENSION AND AXLE FRONT SUSPENSIONSA±47
WhereEverybodyKnowsYourName

REAR DRIVE SHAFT INSTALLATION
SA0S4±02
1. INSTALL DRIVE SHAFT
(a) Insert the outboard joint side of the drive shaft to the axle hub.
NOTICE:
wBe careful not to damage the boots, end cover and speed
sensor rotor of the drive shaft, and oil seal of the axle hub.
w Make sure the outboard joint side of the drive shaft does
not bend too much.
(b) Align the matchmarks on the side gear shaft and drive shaft.
(c) Apply a light coat of engine oil on the threads of the bolt.
(d) Install the 6 hexagon bolts and 2 washers.
(e) Using a 10 mm hexagon wrench, torque the bolts.
Torque: 83 N Vm (850 kgf Vcm, 64 ft Vlbf)
2. INSTALL EXHAUST PIPE
3. INSTALL LOCK NUT, LOCK CAP AND NEW COTTER PIN
Torque: 289 N Vm (2,950 kgf Vcm, 213 ft Vlbf)
4. INSTALL REAR WHEEL AND LOWER VEHICLE
±
SUSPENSION AND AXLE REAR DRIVE SHAFTSA±67
WhereEverybodyKnowsYourName

ECU Power Source Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned on, battery voltage
is applied to the terminal IG SW of the ECU, and the
main relay control circuit in the ECU sends a signal to
the terminal M±REL of the ECU, switching on the
main relay. This signal causes current to flow to the
coil, closing the contacts of the main relay and supply-
ing power to the terminals +B and +B1 of the ECU.
If the ignition switch is turned off, the ECU continues
to switch on the main relay for a maximum of 2 se-
conds for the initial setting of the ISC valve.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
See next page for the DIAGNOSTIC CHART.
WIRING DIAGRAM
TR±124±
ENGINE TROUBLESHOOTING Circuit Inspection
WhereEverybodyKnowsYourName

DIAGNOSTIC CHART
DIAGNOSTIC
CHART
Check for short in all the harness and
components connected to IGN fuse.
Check voltage of terminal M±REL.
Check for open in harness and connector
between battery and ECU.
Check and replace ECU.
Replace ignition switch.
Repair or replace harness or
connector.
Repair or replace harness or
connector.
Check for open and short in harness and
connector between terminal M REL and body
ground.
Replace EFT main relay.
Check voltage of terminal IGSW.
Check IGN fuse.
Check continuity between terminals E1 and
body ground.
Check voltage of ECU power source.
Proceed to next circuit inspection
shown on matrix chart (See page
TR±35
).
Check ignition switch.
Check EFT fuse.
Check EFT main relay.
Check and repair or harness or connector
between EFI fuse and battery.
Check for short in all the harness and
components connected to EFI fuse.
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±125
WhereEverybodyKnowsYourName

NGOK
OKNG
NGOK
INSPECTION PROCEDURE
1Check voltage between terminals + B, + B1 and E1 of engine & ECT ECU connecto\
r.
C
OK
P(2) Connect the Check Harness A.(See page TR±30)
(2) Turn ignition switch on.
Measure voltage between terminals + B, + B1 and E1
of engine & ECT ECU connector.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
2Check for open in harness and connector between terminals E1 of engine &\
ECT ECU and body
ground (See page IN±27).
Repair or replace harness or connector.
3Check voltage between terminal IG SW of engine & ECT ECU connector and b\
ody ground.
C
OK
PTurn ignition switch on.
Measure voltage between terminal IG SW of engine &
ECT ECU connector and body ground.
Voltage: 10 ± 14 V
Go to step 6.
TR±126
±
ENGINE TROUBLESHOOTING Circuit Inspection
WhereEverybodyKnowsYourName

OKNG
OKNG
4Check IGN Fuse.
C
OK
PRemove IGN fuse from J/B No.1.
Check continuity of IGN fuse.
Continuity.
Check for short in all the harness and components con-
nected to IGN fuse (See attached wiring diagram).
5Check ignition switch.
C
OK
PRemove under cover and finish panel.
Check continuity between terminals.
continuity
Replace ignition switch.
Check and repair harness and connector between
battery and ignition switch, ignition switch and en-
gine & ECT ECU.
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±127
WhereEverybodyKnowsYourName

OKNG
OKNG
6Check voltage between terminal M±REL of engine & ECT ECU connector and bod\
y ground.
C
OK
PTurn ignition switch on.
Measure voltage between terminal M±REL of engine &
ECT ECU connection and body ground.
Voltage: 10 ± 14 V
Check and replace engine & ECT ECU.
7Check EFI
C
OK
PRemove EFI fuse R/B No.2.
Check continuity of EFI fuse.
Continuity
Rep
TR±128
±
ENGINE TROUBLESHOOTING Circuit Inspection
WhereEverybodyKnowsYourName