check engine LEXUS SC400 1991 Service Repair Manual

DESCRIPTION
The alternator is a small, high±rpm, high±performance type with an\
IC regulator incorporated. The IC regula-
tor uses integrated circuits and controls the voltage produced by the alter\
nator.
PRECAUTIONS
1. Check that the battery cables are connected to the correct terminals.
2. Disconnect the battery cables when the battery is given a quick charge.
3. Do not perform tests with a high voltage insulation resistance tester.
4. Never disconnect the battery when the engine is running. CH±2
±
CHARGING SYSTEM Description, Precautions
WhereEverybodyKnowsYourName

ON±VEHICLE INSPECTION
1. INSPECT BATTERY SPECIFIC GRAVITY ANDELECTROLYTE LEVEL
(a) Check the specific gravity of each cell.
Standard specific gravity:
1.27±1.29 when fully charged at 20 5C (68 5F)
If gravity is less than specification, charge the battery.
(b) Check the electrolyte quantity of each cell.
If insufficient, refill with distilled (or purified) water.
HINT: Check the indicator as shown in the illustration.
2. CHECK BATTERY TERMINALS, FUSIBLE LINKS AND FUSES
(a) Check that the battery terminals are not loose orcorroded.
(b) Check the fusible links and fuses for continuity.
H±fuse: ALT 150A AM1 100A
AM2 30A
M±fuse: IG SW 40A
Fuse: IGN 7.5A ENGINE 7.5A
INJ 30A
3. INSPECT DRIVE BELTHINT: A belt tensioner is used, so checking the belt tension
is not necessary.
(a) Visually check the drive belt for excessive wear, frayedcords, etc.
If necessary, replace the drive belt.
HINT:
w Cracks on rib side of a drive belt are considered
acceptable. If the drive belt has chunks missing from the
ribs, it should be replaced.
w The drive belt tension can be released by turning the
belt tensioner counterclockwise. The pulley bolt for the
belt tensioner has a left±hand thread.
±
CHARGING SYSTEM On±Vehicle InspectionCH±5
WhereEverybodyKnowsYourName

(b) Check the belt tensioner operation.w Check that the belt tensioner moves downward
when the drive belt is pressed down at the points
indicated in the illustration with approx. 98 N ( 10
kgf, 22.0 lbf) of force.
w Check the alignment of the belt tensioner pulley to
make sure the drive belt has not slipped off the
pulley.
If necessary, replace the belt tensioner.
w Check that the arrow mark on the belt tensioner falls
within area A of the scale.
If it is outside area A, replace the drive belt.
HINT:
w When a new belt is installed, it should lie within area B.
If not, the drive belt is not correct.
w After installing a belt, check that it fits properly in the
ribbed grooves.
w Check by hand to confirm that the belt has not slipped
out of the groove on the bottom of the pulley.
4. REMOVE ENGINE UNDER COVER
5. VISUALLY CHECK ALTERNATOR WIRING AND LISTEN FOR ABNORMAL NOISES
(a) Check that the wiring is in good condition.
(b) C h e c k t h a t t h e r e i s n o a bnormal noise from the
alternator while the engine is running.
6. INSPECT CHARGE WARNING LIGHT CIRCUIT (a) Warm up the engine and then turn it off.
(b) Turn off all accessories.
(c) Turn the ignition switch ON. Check that the charge
warning light is lit.
(d) Start the engine. Check that the light goes off.
If the light does not go off as specified, troubleshoot the
charge light circuit.
CH±6
±
CHARGING SYSTEM On±Vehicle Inspection
WhereEverybodyKnowsYourName

7. INSPECT CHARGING CIRCUIT WITHOUT LOADHINT: If a battery/alternator tester is available, connect the
tester to the charging circuit as per manufacturer's instruc-
tions.
(a) If a tester is not available, connect a voltmeter andammeter to the charging circuit as follows:
w Disconnect the wire from terminal B of the
alternator and connect it to the negative (±) probe
of the ammeter.
w Connect the positive (+) probe of the ammeter to
terminal B of the alternator.
w Connect the positive (+) probe of the voltmeter to
terminal B of the alternator.
w Ground the negative (±) probe of the voltmeter.
(b) Check the charging circuit as follows:
With the engine running from idling to 2,000 rpm, check the
reading on the ammeter and voltmeter.
Standard amperage: 10 A or less
Standard voltage: 13.9±15.1 V at 25 5C (77 5F)
13.5±14.3 V at 115 5C (239 5F)
If the voltmeter reading is greater than standard voltage, re-
place the IC regulator.
If the voltmeter reading is less than standard voltage, check
the IC regulator and alternator as follows:
w Remove the engine under cover.
w With terminal F grounded, start the engine and
check the voltmeter reading of terminal B.
w If the voltmeter reading is greater than standard
voltage, replace the IC regulator.
w If the voltmeter reading is less than standard
voltage, check the alternator.
w Reinstall the engine under cover.
±
CHARGING SYSTEM On±Vehicle InspectionCH±7
WhereEverybodyKnowsYourName

8. INSPECT CHARGING CIRCUIT WITH LOAD(a) With the engine running at 2,000 rpm, turn on the highbeam headlights and place the heater blower switch at
ºHIº.
(b) Check the reading on the ammeter.
Standard amperage: 30 A or more
If the ammeter reading is less than standard amperage, re-
pair the alternator. (See page CH±9)
HINT: With the battery fully charged, the indication will some-
times be less than standard amperage.
9. REINSTALL ENGINE UNDER COVER
CH±8
±
CHARGING SYSTEM On±Vehicle Inspection
WhereEverybodyKnowsYourName

PREPARATION
SST (SPECIAL SERVICE TOOLS)
 Illustration Part No. Part Name Note
 


 

09278±54012
 

Drive Shaft Holding Tool
 


Hydraulic pump pulley
 




 



09286±46011
 




Injection Pump
Spline Shaft Puller
 




Hydraulic pump pulley
 




 



09620±30010
 




Steering Gear Box
Replacer Set
 




 




 



(09627±30010)
 




Steering Sector Shaft
Bushing Replacer
 




Oil seal for hydraulic motor
 




 




(09631±00020)
 




(Handle)
 




Oil seal for hydraulic motor
 




 




09631±10030
 




Oil Seal Remover
 




Oil seal for hydraulic pump
 




 




09843±18020
 




Diagnosis Check
Wire 




RECOMMENDED TOOLS 

Illustration
 

Part No.
 

Part Name
 

Note
 




 




09025±00010
 




Small Torque
Wrench 




For measuring preload
 


 

09082±00015 


TOYOTA
Electrical tester 


 




 



09200±00010
 




Engine Adjust
Kit
 




 




 



09258±00030
 



Hose Plug Set
 




Plug for the vacuum hose, oil hose ect.
 




 




09904±00010
 




Expander
Set
 




Oil seal for hydraulic pump
 




 




09905±00013
 




Snap Ring
Pliers
 




Oil seal for hydraulic pump
CO±4±
COOLIING SYSTEM Preparation
WhereEverybodyKnowsYourName

CHECK AND REPLACEMENT OF
ENGINE COOLANT
1. CHECK ENGINE COOLANT LEVEL AT RESERVE TANKThe coolant level should be above the ºCOLD LEVELº at nor-
mal temperature (20 5C (68 5F)).
If low, check for leaks and add coolant up to the ºCOLD LEV-
ELº.
2. CHECK ENGINE COOLANT QUALITY There should not be any excessive deposits of rust or scales
around the radiator cap or reservoir tank filler hole, and the
coolant should be free from oil.
If excessively dirty, clean the coolant passages and replace
the coolant.
3. REPLACE ENGINE COOLANT (a) Remove the radiator cap from the reservoir tank.
CAUTION: To avoid the danger of being burned, do not
remove the cap while the engine and radiator are still hot,
as fluid and steam can be blown out under pressure.
(b) Remove the filler plug from the water inlet housing.
(c) Loosen the three drain plugs on the radiator and
cylinder block, drain the coolant from the radiator and
engine.
(d) Clean the coolant passages.
(e) Close the three drain plugs.
Torque (Engine drain plug):
18 NVm (180 kgf Vcm, 13 ft Vlbf)
CO±6±
COOLIING SYSTEM Check and Replacement of Engine Coolant
WhereEverybodyKnowsYourName

(f) Slowly add coolant to water inlet housing until it is full.w Use a good brand of ethylene±glycol base coolant,
mixed according to the manufacturer's directions.
w Using coolant which includes more than 50%
ethylene±glycol (but not more 70%) than is
recommended.
NOTICE:
w Do not use alcohol type coolant.
w The coolant should be mixed with demineralized water or
distilled water.
Capacity (w/ Heater): 10.8 liters (11.4 US qts, 9.5 lmp. qts)
(g) Reinstall a new gasket and filler plug to the water inlethousing.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
(h) Slowly add coolant to reservoir tank until it is full.
(i) Reinstall the radiator cap.
(j) Bleed the cooling system.
w Start the engine, and open the heater water valve.
w Maintain the engine speed at 2,000 rpm, and warm
up the engine.
(k) Check for leaks.
(l) Recheck the coolant level and refill as necessary.
±
COOLIING SYSTEM Check and Replacement of Engine CoolantCO±7
WhereEverybodyKnowsYourName

INSPECTION OF THERMOSTAT
INSPECT THERMOSTATHINT: The thermostat is numbered with the valve opening
temperature.
(a) Immerse the thermostat in water and gradually heat thewater.
(b) Check the valve opening temperature.
Valve opening temperature: 80±84 5C (176±183 5F)
If the valve opening temperature is not as specified, replace
the thermostat.
(c) Check the valve lift.
Valve lift:
10 mm (0.39 in.) or more at 95 5C (203 5F)
If the valve lift is less than specification, replace the thermo-
stat.
(d) Check that the valve spring is tight when the thermostat
is fully closed.
If necessary, replace the thermostat.
INSTALLATION OF THERMOSTAT
(See Components on page CO±12)
1. PLACE THERMOSTAT IN WATER INLET HOUSING (a) Install a new gasket to the thermostat.
(b) Insert the thermostat into the water inlet housing withthe jiggle valve facing straight upward.
HINT: The jiggle valve may be set within 30 5 of either side of
the prescribed position.
2. INSTALL WATER INLET Install the water inlet with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
3. FILL WITH ENGINE COOLANT (See page CO±7)
4. START ENGINE AND CHECK FOR LEAKS
±
COOLIING SYSTEM ThermostatCO±13
WhereEverybodyKnowsYourName

RADIATOR
CLEANING OF RADIATOR
Using water or a steam cleaner, remove any mud and dirt
from the radiator core.
NOTICE: If using a high pressure type cleaner, be careful
not to deform the fins of the radiator core. If the cleaner
nozzle pressure is 2,942±3,432 kPa (30±35 kgf/cm2,
427±498 psi), keep a distance at least 40±50 cm
(15.75±19.69 in.) between the radiator core and cleaner
nozzle.
INSPECTION OF RADIATOR
1. REMOVE RADIATOR CAP FROM RESERVOIR TANK
2. INSPECT RADIATOR CAPUsing a radiator cap tester, pump the tester and measure the
relief valve opening pressure.
Standard opening pressure:
74±103 kPa
(0.75±1.05 kgf/cm, 10.7±14.9 psi)
Minimum opening pressure:
59 kPa (0.6 kgf/cm, 8.5 psi)
If the opening pressure is less than minimum, replace the ra-
diator cap.
3. INSPECT COOLING SYSTEM FOR LEAKS (a) Fill the radiator with coolant and attach a radiator captester to the reservoir tank.
(b) Warm up the engine.
(c) Pump it to 118 kPa (1.2 kgf/cm2, 17.1 psi), check that pressure does not drop.
If the pressure drops, check for leaks as the hoses, radiator
or water pump. If no external leaks are found, check the heat-
er core, cylinder block and head.
4. REINSTALL RADIATOR CAP
CO±14
±
COOLIING SYSTEM Radiator
WhereEverybodyKnowsYourName