rotors LEXUS SC300 1991 Service Repair Manual

The speed sensor detects the wheel speed and sends the ap-
propriate signals to the ECU. These signals are used for control
of both the ABS and TRAC control systems. The front and rear
rotors each have 48 serrations. When the rotors rotate, the mag-
netic field emitted by the permanent magnet in the speed sensor
generates an AC voltage. Since the frequency of this AC voltage
changes in proportion to the speed of the rotors (wheels), the
frequency is used by the ECU to detect the speed of each wheel.
BR3583
BR3582
DTC31, 32,
33, 34Speed Sensor Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
31, 32,
33, 34
Detection of any of conditions (1) through (3):
(1) At vehicle speed of 10 km/h (6 mph) or more, pulses are not input for 5 sec.
(2) Momentary interruption of the vehicle speed sen- sor signal occurs at least 7 times in the time be-
tween switching the ignition switch ON and switch-
ing it OFF.
(3) Abnormal fluctuation of speed sensor signals with the vehicle speed 20 km/h (12 mph) or more.

Right front, left front, right rear and left rear
speed sensor.

Open or short in each speed sensor circuit.

ECU
Hint: DTC No. 31 is for the right front wheel speed sensor.
DTC No. 32 is for the left front wheel speed sensor.
DTC No. 33 is for the right rear wheel speed sensor.
DTC No. 34 is for the left rear wheel speed sensor.
Fail safe function: If trouble occurs in the speed sensor circuit, the E\
CU prohibits TRAC control.
BR±190
±
BRAKE SYSTEM TRACTION CONTROL SYSTEM (TRAC)
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DTC
31, 32,
33, 34,35, 36
Speed Sensor Circuit
CIRCUIT DESCRIPTION
The speed sensor detects the wheel speed and sends the ap-
propriate signals to the ECU. These signals are used for control
of both the ABS and TRAC control systems. The front and rear
rotors each have 48 serrations. When the rotors rotate, the
magnetic field emitted by the permanent magnet in the speed
sensor generates an AC voltage. Since the frequency of this
AC voltage changes in proportion to the speed of the rotors
(wheels) the frequency is used by the ECU to detect the speed
of each wheel.
BR3583
BR3582
DTC No.DTC Detecting ConditionTrouble Area
31, 32,
33, 34
Detection of any of conditions (1) through (3):
(1) At vehicle speed of 10 km/h (6 mph) or more,
pulses are not input for 5 sec.
(2) Momentary interruption of the vehicle speed sen-
sor signal occurs at least 7 times in the time between
switching the ignition switch ON and switching it OFF.
(3) Abnormal fluctuation of speed sensor signals with
the vehicle speed 20 km/h (12 mph) or more.

Right front, left front, right rear and left rear
speed sensor.

Open or short in each speed sensor circuit.

ECU
35
Vehicle speed sensor signal is not input for about 1 sec.
while the left front and right rear with the vehicle speed
sensor signals are being checked IG switch ON.
Open in left front, right rear speed sensor cir-
cuit.

ECU
36
Vehicle speed sensor signal is not input for about 1 sec.
while the right front and left rear vehicle speed sensor
signals are being checked with the IG switch ON.
Open in right front, left rear speed sensor cir-
cuit.

ECU
HINT: DTC No. 31 is for the right front wheel speed sensor.
DTC No. 32 is for the left front wheel speed sensor.
DTC No. 33 is for the right rear wheel speed sensor.
DTC No. 34 is for the left rear wheel speed sensor.
Fail safe function: If trouble occurs in the speed sensor circuit, the ECU cuts off current to the ABS
solenoid relay and prohibits ABS control.
BR±118
±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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(b) Using a plastic±faced hammer, carefully tap out the front
housing.
(c) Remove the O±ring from the casing.
7. REMOVE FRONT THRUST WASHER AND DRIVE SHAFT
8. REMOVE DRIVE AND DRIVEN ROTORS
9. REMOVE REAR THRUST WASHER
10. REMOVE CASING (a) Remove the casing.
(b) Remove the O±ring from the rear housing.
11. REMOUNT REAR HOUSING HINT: Mount the parts in a vise as shown in the illustration.
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)CO±33
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4. INSPECT DRIVE AND DRIVEN ROTORS
A. Install casing and rotors to rear housingFace the dot mark of the rotors upward.
B. Inspect rotor side clearance HINT: Before measuring the clearance, remove one side of
the rotor.
Using a feeler gauge and precision straight edge, measure
the clearance between the rotor and precision straight edge.
Standard side clearance:
Drive rotor 0.02 mm (0.0008 in.)
Driven rotor 0.03 mm (0.0012 in.)
Maximum side clearance: Drive rotor 0.03 mm (0.0012 in.)
Driven rotor 0.04 mm (0.0016 in.)
If the clearance is greater than maximum, replace the rotors
as a set. If necessary, replace the housings.
C. Inspect rotor body clearance Using a feeler gauge, measure the clearance between the
driven rotor and casing.
Standard body clearance: 0.05±0.09 mm
(0.0020±0.0035 in.)
Maximum body clearance: 0.10 mm (0.0039 in.)
If the clearance is greater than maximum, replace the rotors
as a set. If necessary, replace the casing.
D. Inspect rotor tip clearance Using a feeler gauge, measure the clearance of all the six
drive rotor tips between the drive and driven rotors.
Standard tip clearance: 0.02 mm (0.0008 in.)
Maximum tip clearance: 0.03 mm (0.0012 in.)
If the clearance is greater than maximum, replace the rotors
as a set.
E. Remove rotors and causing from rear housing
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)CO±35
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3. REMOUNT REAR HOUSINGHINT: Mount the parts in a vise as shown in the illustration.
4. INSTALL CASING HINT: If rubber from the O±rings adheres to the O±ring instal-
lation location, replace the casing.
(a) Install a new O±ring to the rear housing groove.
(b) Align the pin hole of the casing with the straight pin onthe rear housing, and install the casing.
5. INSTALL REAR THRUST WASHER
6. INSTALL DRIVEN AND DRIVE ROTORS Install the d rive and driven rotors with the dot mark facing up-
ward.
7. INSTALL DRIVE SHAFT
8. INSTALL FRONT THRUST WASHER
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (Hydraulic Pump)CO±39
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DISASSEMBLY OF HYDRAULIC MOTOR
(See Components on page CO±50)
1. MOUNT MOTOR HOUSING Slightly mount the motor housing in a vise.
NOTICE: Be careful not to damage the motor housing.
2. REMOVE MOTOR COVER (a) Remove the four bolts and motor cover.
(b) Remove the O±ring from the motor housing.
3. REMOVE REAR THRUST WASHER AND DRIVE SHAFT
4. REMOVE DRIVE AND DRIVEN ROTORS
5. REMOVE FRONT THRUST WASHER
INSPECTION OF HYDRAULIC MOTOR
1. INSPECT DRIVE AND DRIVEN ROTORS (a) Install the drive and driven rotor to the motor housingwith the dot mark facing upward.
(b) Using a feeler g auge and precision straight edge,
measure the side clearance between the rotor and
precision straight edge.
Standard side clearance: 0.01±0.04 mm
(0.0004±0.0016 in.)
Maximum side clearance: 0.05 mm (0.0020 in.)
If the clearance is greater than maximum, replace the rotors
as a set. If necessary, replace the motor assembly.
±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)CO±51
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HINT: When replacing the rotors, select the rotor set accord-
ing to the imprinted mark on the motor housing.
 Imprinted mark on housing Rotor set
116906±50010 2 16906±50020 3 16906±50030
2. INSPECT OIL CLEARANCE OF DRIVE SHAFT(a) Using a caliper gauge, measure the shaft hole insidediameter of the housing and cover.
Shaft hole inside diameter: 14.000±14.011 mm
(0.5512±0.5516 in.)
(b) Using a micrometer, measure the drive shaft diameter.
Shaft diameter: 13.973±13.984 mm
(0.5501±0.5506 in.)
(c) Subtract the drive shaft diameter measurement from the
shaft hole diameter measurement.
Standard clearance: 0.016±0.038 mm
(0.0006±0.0015 in.)
Maximum clearance: 0.04 mm (0.0016 in.)
If the clearance is greater than maximum, replace the shaft.
If necessary, replace the motor assembly.
CO±52±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)
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ASSEMBLY OF HYDRAULIC MOTOR
(See Components on page CO±50)
HINT:
w Thoroughly clean all parts to be assembled.
w Before installing the parts, apply new fluid to all sliding
and rotating surfaces.
1. MOUNT MOTOR HOUSING Slightly mount the motor housing in a vise.
NOTICE: Be careful not to damage the motor housing.
2. INSTALL FRONT THRUST WASHER
3. INSTALL DRIVEN AND DRIVE ROTORS Install the d rive and driven rotors with the dot mark facing up-
ward.
4. INSTALL DRIVE SHAFT
5. INSTALL REAR THRUST WASHER
6. INSTALL MOTOR COVER (a) Install a new O±ring to the motor housing groove.
(b) Install the motor cover with the four bolts.
Torque: 28 N Vm (290 kgf Vcm, 21 ft Vlbf)
CO±54±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)
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20. REMOVE DISTRIBUTOR CAPSLoosen the 3 bolts, and remove the distributor cap.
Remove the 2 distributor caps.
HINT: Arrange the distributor caps (RH side and LH side).
21. REMOVE DISTRIBUTOR ROTORS Loosen the 2 bolts, and remove the distributor rotor.
Remove the 2 distributor rotors.
HINT: Arrange the distributor rotors (RH side and LH side).
22. REMOVE DISTRIBUTOR HOUSINGS
(a) RH Distributor Housing: Disconnect the camshaft position sensor connector.
(b) Remove the 3 bolts and distributor housing. Remove the 2 distributor housings.
23. REMOVE GENERATOR
(a) Disconnect the generator connector.
(b) Remove the cap and nut, and disconnect the generator wire.
(c) Remove the bolt, and disconnect the transmission oil cooler pipe bracket from the generator.
(d) Remove the nut and generator.
24. REMOVE DRIVE BELT TENSIONER Remove the bolt, 2 nuts and belt tensioner.
EG±52
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1UZ±FE ENGINE ENGINE MECHANICAL
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19. INSTALL DRIVE BELT TENSIONERInstall the belt tensioner with the bolt and 2 nuts.
Torque: 16 N Vm (160 kgf Vcm, 12 ft Vlbf)
HINT: Use bolt 106 mm (4.18 in.) in length.
20. INSTALL GENERATOR
(a) Install the generator and transmission oil cooler pipe bracket with the bolt and nut.
Torque: 37 N Vm (380 kgf Vcm, 27 ft Vlbf)
(b) Connect the generator connector.
(c) Connect the generator wire with the nut and cap.
21. INSTALL RH DISTRIBUTOR HOUSING
Install the distributor housing with the 3 bolts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT:
w The RH distributor housing is marked with ªRº.
w Each bolt length is indicated in the illustration.
Bolt length:
38 mm (1.50 in.) for A
96 mm (3.78 in.) for B
22. INSTALL LH DISTRIBUTOR HOUSING Install the distributor housing with the 3 bolts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
HINT:
w The LH distributor housing is marked with ªLº.
w Each bolt length is indicated in the illustration.
Bolt length:
38 mm (1.50 in.) for A
80 mm (3.15 in.) for B
23. INSTALL DISTRIBUTOR ROTORS
(a) Align the protrusion of the distributor rotor with the groove the
camshaft timing pulley.
(b) Install the distributor rotor with the 2 bolts. Install the 2 distributor rotors.
Torque: 3.8 N Vm (39 kgf Vcm, 34 in. Vlbf)
±
1UZ±FE ENGINE ENGINE MECHANICALEG±65
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