1991 LEXUS SC400 cooling

No.Gauge reading kPa (kgf/cm2, psi)ConditionProbable causeRemedy
Pressure low at both low and high
pressure sides
Pressure too high at both low and
high pressure sides

Insufficient cooling

Bubbles seen in
sight glass

Insufficient cooling

Frost on tubes from
receiver to
unit
Replace receiver
Insufficient refrigerant(1) Check for gas
leakage with gas
leak tester and
repair if
necessary
(2) Add refrigerant
until bubbles
disappear
Refrigerant flow
obstructed by dirt in
receiver
Insufficient coolingInsufficient cooling of
condenser(1). Clean condenser
(2). Check fan motoroperation
(1). Check amount ofrefrigerant
If refrigerant is
overcharged
(2). Recover refrigeran
t
(3). Evacuate air and charge proper
amount of purified
refrigerant
Refrigerant
overcharged
(1). Replace receiver
(2). Check compres- sor oil to see if
dirtyAir present in system

Insufficient cooling

Frost in Large
amount of dew on
piping at low
pressure side Expansion valve
improperly mounted,
heat sensing tube
defective
(Open too wide)(1) Check heat sensing
tube installation
condition
If (1) is normal
(2) Check expansion valve and replace
if defective
(3). Remove air insystem through
repeatedly
evacuating air
NOTICE:
wAlways recover refrigerant before removing the parts in the refrigerant line a\
nd evacuating air.
w Evacuate air and charge proper amount of purified refrigerant after installing th\
e parts in the
refrigerant line.
HINT at 6:
These gauge indication are for when the refrigeration system has been op\
ened and the refrigerant charged
without evacuating air.
±
AIR CONDITIONING SYSTEM TroubleshootingAC±101
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REFRIGERANT VOLUME
INSPECTION OF REFRIGERANT
VOLUME
1. RUN ENGINE AT IDLE SPEED
2. OPERATE A/C AT MAXIMUM COOLING FOR A FEWMINUTES
3. INSPECT AMOUNT OF REFRIGERANT Observe the sight glass on the liquid tube.
ItemSymptomAmount of refrigerantRemedy
1
Bubbles present in sight glassInsufficient*(1) Check for gas leakage with
gas leak tester and repair
if necessary
(2) Add refrigerant until bubbles disappear
2No bubbles present in sight
glassNone, sufficient or too muchRefer to items 3 and 4
3
No temperature difference
between compressor inlet and
outletEmpty or nearly empty(1) Check for gas leakage withgas leak tester and repair
if necessary
(2) Add refrigerant until bubbles disappear
4
Temperature between
compressor inlet and outlet is
noticeably differentProper or too muchRefer to items 5 and 6
5
Immediately after air conditioner
is turned off, refrigerant in sight
glass stays clearToo much(1) Recover refrigerant
(2) Evacuate air and charge
proper amount of
purified refrigerant
6
When air conditioner is turned
off, refrigerant foams and then
stay clearProper
±
*: Bubbles in the sight glass with ambient temperatures higher can be cons\
idered normal if cooling is sufficient.
REFRIGERANT CHARGE VOLUME
Specified amount: 950 + 50 g (33.44 + 1.76 oz)
±
AIR CONDITIONING SYSTEM Refrigerant VolumeAC±103
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EVAPORATOR
REMOVAL OF EVAPORATOR
1. DISCONNECT NEGATIVE (±) CABLE FROM BATTERY
2. RECOVER REFRIGERANT IN REFRIGERATION SYSTEMSee page AC±16
3. REMOVE ABS ACTUATOR
See page BR±48
4. REMOVE LIQUID TUBE AND SUCTION TUBE Remove two bolts and both tubes.
5. REMOVE EQUALIZER TUBE FROM EPR
Remove the bole and the tube.
NOTICE: Cap the open fittings immediately to keep mois-
ture out of the system.
6. REMOVE UNDER COVER GLOVE BOX AND SIDE AIR DUCT
7. DISCONNECT CONNECTORS AND REMOVE POWER STEERING RELAY BOX COOLING FAN COMPUTER AND
TRC COMPUTER
AC±122
±
AIR CONDITIONING SYSTEM Evaporator
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INSTALLATION OF EVAPORATOR
1. INSTALL REMOVAL PARTSInstall the removal parts in reverse order of removal proce-
dure.
HINT:
wThe tightening torque for the bolt used to install the
expansion valve on the evaporator is shown below.
Specified torque: 5.4 N Vm (55 kgf Vcm, 48 ft Vlbf)
w The tightening torque for the bolts used to install the
liquid tube and suction tube to the cooling is shown
below.
Specified torque: 10 N Vm (100 kgf Vcm, 7 ft Vlbf)
w The tightening torque specified for the bolt used to
install the equalizer tube to EPR is shown below.
Specified torque: 25 N Vm (250 kgf Vcm, 18 ft Vlbf)
2. IF EVAPORATOR WAS REPLACED, ADD COMPRESSOR
OIL TO EVAPORATOR
Add 40±50 cc (1.4±1.7 fl.oz)
Compressor oil: ND OIL 6,
SUNISO NO. 5 GS or equivalent
3. EVACUATE AIR IN REFRIGERATION SYSTEM ANDCHARGE WITH REFRIGERANT
Specified amount: 950 + 50 g (33.44 + 1.76 oz)
4. INSPECT FOR LEAKAGE OF REFRIGERANT
Using a gas leak tester, check for leakage of refrigerant.
AC±124
±
AIR CONDITIONING SYSTEM Evaporator
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SERVICE SPECIFICATIONS
SERVICE DATA
AT0GH±02 Line pressure (wheel locked)\
 \

 \
 \
382±441 kPa 3.9±4.5 kgf/cm255±64 psi
 Engine idling D position\
 \

 \
 \
637±716 kPa 6.5±7.3 kgf/cm292±104 psi
 R position\
 \

\
1,265±1,402 kPa 12.9±14.3 kgf/cm2183±203 psi AT stall (Throttle valve opened) D position\
 \

 \
 \
1,726±2,060 kPa 17.6±21.0 kgf/cm2250±298 psi R position\
 \

 ECM SLN termina lNot ground\
 \
177±255 kpa 1.8±2.6 kgf/cm226±37 psi
 Ground\
 \
0
 Engine stall revolution\
 \
2,200+150 RPM
 Time lag N position " D position\
 \
Less than 1.2 seconds
 N position " R position\
 \
Less than 1.5 seconds
 Engine idle speed (Cooling fan and A/C OFF
)N position\
 \
650 RPM
 \
 \
Boot end face and inner cable stopper Throttle cable adjustment (Throttle valve fully closed)\
 \

 \
 \
0±1 mm 0±0.04 in.
 Torque converter clutch installing (Correct distance)\
 \
17.1mm 0.673 in.
 Drive plate runout Limit\
 \
0.20 mm 0.0079 in.
SHIFT POINT (Kick±down foot switch activated)
 Shift position Shifting point Vehicle speed km/h (mph)2
  Throttle valve fully opened 1"2 67±71 (42±44)
  2" 3 118±124 (73±77)
  3" O/D (NORM) 170±177 (106±110)
  3" O/D (PWR) 179±186 (111±116)
 D position (NORM or PWR) O/D "3 164±170 (102±106)
  3" 2 105±111 (65±69)  2" 1 53±57 (33±35) 

2 iti
 

Throttle valve fully opened 1
"2
 

67±71 (42±44)
 2 position
(NORM or PWR) 3
" 2 106±112 (66±70)
 
(NORM or PWR)
 2" 1 53±57 (33±35)
 L position Throttle valve fully opened 3 "2 104±109 (65±68)
 
L osition
(NORM or PWR) 2" 1 57±63 (35±39)
±
A340E (1UZ±FE) AUTOMATIC TRANSMISSION SERVICE SPECIFICATIONSAT±121
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( Coolant Level Warning Switch)
REMOVAL AND INSTALLATION OF COOLANT
LEVEL WARNING SWITCH
1. REMOVE COOLANT LEVEL WARNING SWITCH(a) Disconnect the connector.
(b) Remove the boot.
(c) Using the notches in the head of switch, turn the switchcounterclockwise and remove it.
NOTICE: Do not remove when engine is hot.
2. INSTALL COOLANT LEVEL WARNING SWITCH For installation, follow the removal procedure in reverse.
INSPECTION OF COOLANT LEVEL WARNING
SWITCH
1. INSPECT COOLANT LEVEL WARNING SWITCH(Continuity)
(a) Remove the radiator cap and open the radiator drainclock.
NOTICE: Do not remove when engine is hot.
(b) Drain the coolant about 1 liter. (1.1 US qts, 0.9 lmp. qts)
(c) Check that there is continuity between terminals (float down).
(d) Close radiator drain cock and fill the cooling system with
coolant.
(e) Check that there is no continuity between terminals (float up).
If continuity is not as specified, replace the switch.
2. INSPECT COOLANT LEVEL WARNING LIGHT (a) Disconnect the connector from the coolant level warning
switch and ground terminal 1 on the wire harness side
connector.
(b) Start the engine, check that the warning light lights up.
If the warning light does not light up, inspect the bulb or wire
harness.
±
BODY ELECTRICAL SYSTEM Combination MeterBE±117
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Shift Lock ECU
Tilt and Power
Telescopic ECU
Airbag ECU
Cruise Control ECU Engine ECUABS and Traction ECU
(w/ Traction System) or
ABS ECU
(w/o Traction System)
Theft Deterrent and
Door Lock ECU
(w/ Traction System)
Traction ECU
Remote Control Mirror ECU A/C Control Amplifier
PPS ECU
Engine Cooling Fan ECU
Component to be aligned
Section of repair manual
for relevant model year
Front Wheels Suspension and Axle (SA) section
Rear Wheels Suspension and Axle (SA) section
Propeller Shaft Propeller Shaft (PR) section
2. BRAKE SYSTEM
The brake system is one of the most important safety components. Always \
follow the directions and
notes given in section BR of the repair manual for the relevant model ye\
ar when handling brake sys-
tem parts.
NOTICE: When repairing the brake master cylinder or TRAC system, bleed t\
he air out of the TRAC
system.
3. DRIVE TRAIN AND CHASSIS
The drive train and chassis are components that can have great effects on the running performance
and vibration resistance of the vehicle. After installing components in \
the sections listed in the table
below, perform alignments to ensure correct mounting angles and dimensions. P\
articularly accurate
repair of the body must also be done to ensure correct alignment.
HINT: Correct procedures and special tools are required for alignment. Alway\
s follow the directionsgiven in the repair manual for the relevant model year during alignment \
and section DI of this manual.
4. ECU (ELECTRONIC CONTROL UNIT)
Locations of ECUs
INTRODUCTIONIN-8
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SERVICE SPECIFICATIONS
SERVICE DATA
ThermostatValve opening temperature80±845C176±183 5F
Valve liftat 95 5C (203 5F) 10 mm0.39 in.
Radiator capRelief valve opening pressureSTD74±103 kPa
(0.75±1.05 kgf/cm, 10.7±14.9 psi)
Limit 59 kPa 0.6 kgf/cm 8.5 psi
On±vehicle
itifh
Oil pressure1,177±2,452 kPa
inspection for hy-
draulic cooling(12±25 kgf/cm, 171±356 psi)draulic cooling
fan
fan
Hydraulic pumpSpool valve45.8 mm1.803 in.
Rotor side clearanceSTD Drive rotor 0.02 mm0.0008 in.
Driven rotor 0.03 mm0.0012 in.
Limit Drive rotor 0.03 mm0.0012 in.
Driven rotor 0.04 mm0.0016 in.
Rotor body clearanceSTD 0.05±0.09 mm0.0020±0.0035 in.
Limit 0.10 mm0.0039 in.
Rotor tip clearanceSTD 0.02 mm0.0008 in.
Limit 0.03 mm0.0012 in.
Drive shaft bushing inside diameter17.00±17.05 mm0.6693±0.6713 in.
Drive shaft diameter16.97±16.98 mm0.6681±0.6685 in.
Drive shaft oil clearanceSTD 0.02±0.08 mm0.0008±0.0031 in.
Limit 0.08 mm0.0031 in.
Drive shaft preload (rotating torque)0.3 N Vm 3.0 kgf Vcm 2.6 in. Vlbf
Solenoid valve resistanceat cold 7.5±8.5

Hydraulic motorRotor side clearanceSTD0.01±0.04 mm0.0004±0.0016 in.
Limit 0.05 mm0.0020 mm
Drive shaft hole inside diameter14.000±14.011 mm0.5512±0.5516 in.
Drive shaft diameter13.973±13.984 mm0.5501±0.5506 in.
Drive shaft oil clearanceSTD 0.016±0.038 mm0.0006±0.0015 in.
Limit 0.04 mm0.0031 in.
Drive shaft preload (rotating torque)0.3 NVm 3.0 kgf Vcm 2.6 in. Vlbf
Water temp. Resistanceat 80 5C (176 5F)1.48±1.58 k

sensor
CO±64±
COOLIING SYSTEM Service Specifications
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