check engine LEXUS SC400 1991 Service Repair Manual

(b) Apply battery voltage across the terminals.
(c) Check that the air flows from port E to the filter.
If operation is not as specified, replace the VSV.
4. REINSTALL VSV (a) Install the VSV with the bolt.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(b) Connect the following hoses:
(1) Vacuum hose (from EGR valve) to VSV
(2) Vacuum hose (from EGR vacuum modulator) to VSV
(c) Connect the VSV connector.
5. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
INSPECTION OF EGR VACUUM
MODULATOR (Exc. USA Spec.)
1. DISCONNECT VACUUM HOSES FROM EGR VACUUMMODULATOR
Disconnect the three vacuum hoses from ports P, Q and R of
the EGR vacuum modulator.
2. INSPECT EGR VACUUM MODULATOR OPERATION (a) Block ports P and R with your finger.
(b) Blow air into port Q, and check that the air passesthrough to the air filter side freely.
(c) Start the engine, and maintain speed at 2,500 rpm.
(d) Repeat the above test. Check that there is a strong resistance to air flow.
3. RECONNECT VACUUM HOSES TO EGR VACUUM MODULATOR
Connect the three vacuum hoses to the proper locations.
EC±20
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) System
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INSPECTION OF EGR VALVE
(USA Spec.)
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and the negative (±) termi-
nal cable is disconnected from the battery.
2. DISCONNECT EGR VALVE CONNECTOR
3. INSPECT EGR VALVE RESISTANCE Using an ohmmeter, measure the resistance between termi-
nal B1 (or B2) and other terminals (S1, S2, S3 and S4).
Resistance (Cold): 19.9±23.4

4. DRAIN ENGINE COOLANT (See page CO±6)
5. REMOVE EGR VALVE (a) Disconnect the following hoses:(1) Water by±pass hose (from ISC valve) from the EGR
valve
(2) Water by±pass hose (from rear water by±pass joint) from the EGR valve
(b) Remove the two nuts, EGR valve and gasket.
6. INSPECT EGR VALVE
A. Visually inspect EGR valve Check for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
EC±22
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) System
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3. INSPECT EGR VALVECheck for sticking and heavy carbon deposits.
If a problem is found, replace the EGR valve assembly.
4. REINSTALL EGR VALVE (a) Place a new gasket on the EGR valve adaptor.
NOTICE:
w Do not touch the adaptor and EGR valve surfaces of the
gasket with your hand.
w Align the port holes of the gasket and adaptor.
Be careful of the installation direction.
(b) Install the EGR valve with the two nuts.
Torque: 18 N Vm (185 kgf Vcm, 13 ft Vlbf)
(c) Install the vacuum modulator bracket to the EGR valve.
(d) Connect the following hoses:
(1) Vacuum hose (from VSV) to EGR valve
(2) Vacuum hose (from VSV) to EGR vacuum modula- tor
(3) Vacuum hose (from EGR vacuum modulator) to EGR valve
(4) Water by±pass hose (from ISC valve) to the EGR
valve
(5) Water by±pass hose (from rear water by±pass joint) to the EGR valve
5. REFILL WITH ENGINE COOLANT (See page CO±7)
±
EMISSION CONTROL SYSTEMS Exhaust Gas Recirculation (EGR) SystemEC±25
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24. CONNECT CONTROL CABLES TO THROTTLE BODYConnect the following hoses:(1) Accelerator cable
(2) A/T throttle control cable
(3) (w/ Cruise Control System) Cruise control actuator cable
25. INSTALL THROTTLE BODY COVER Install the throttle body cover and hose clamp with the two
bolts and cap nut.
26. C O N N E C T C A B L E TO N E G AT I V E T E R M I N A L O F BATTERY
27. FILL WITH ENGINE COOLANT (See page CO±7)
28. CHECK THAT ENGINE STARTS
ST±34
±
STARTING SYSTEM Starter
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STARTER RELAY
INSPECTION OF STARTER RELAY
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OFBATTERY
CAUTION: Work must be started after approx. 20 seconds or
longer from the time the ignition switch is turned to the
ºLOCKº position and the negative (±) terminal cable is dis-
connected from the battery.
2. REMOVE STATER RELAY LOCATION: In the engine compartment relay box.
3. INSPECT STARTER RELAY
A. Inspect relay continuity
(a) Using an ohmmeter, check that there is continuitybetween terminals 1 and 2.
(b) Check that there is no continuity between terminals 3 and 5.
If continuity is not as specified, replace the relay.
B. Inspect relay operation (a) Apply battery voltage across terminals 1 and 2.
(b) Using an ohmmeter, check that there is continuitybetween terminals 3 and 5.
If operation is not as specified, replace the relay.
4. REINSTALL STARTER RELAY
5. RECONNECT CABLE TO NEGATIVE TERMINAL OF BATTERY
NEUTRAL START SWITCH
(See AT section)
THEFT DETERRENT SYSTEM
(See BE section)
±
STARTING SYSTEM Starter Relay, Neutral Start Switch, Theft Deterrent
SystemST±35
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OKNG
NGOK
NGOK
OKNG
INSPECTION PROCEDURE
1Check operation of brake warning light.
Check that the brake warning light in the instrument panel comes on when the \
parking brake is opera-
tion with the engine running, and the light goes off when the parking brake is not operating.C
Check brake warning light circuit.
2Input signal check.
C
OK
1. See input signal check.
2. Check the indicator light when the parking brake isoperating.
The indicator light goes off when the parking brake
is operating.
Proceed to next circuit inspection shown on matrix
chart.
3Check voltage between terminal PKB of tilt & telescopic ECU connector and bod\
y ground.
C
OK
PRemove tilt & telescopic ECU with connectors still con-
nected.
1. Turn ignition switch ON.
2. Measure voltage between terminal PKB of tilt & telescopic ECU connector and body ground, when
the parking brake lever is operating.
Proceed to next circuit inspection shown on matrix
chart.
4Check for open in harness and connector between tilt & telescopic ECU and brak\
e warning light
(See page IN±33).
.
Repair or replace harness or connector
Check and replace tilt & telescopic ECU.
±
STEERING STEERING COLUMNSR±97
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ON±VEHICLE INSPECTION
CHECK IDLE±UP
SR0FZ±04
1. WARM UP ENGINE
2. TURN AIR CONDITIONER SWITCH OFF
3. CHECK IDLE±UP
(a) Fully turn the steering wheel.
(b) Check that the engine rpm decreases when the air controlvalve hose is pinched.
(c) Check that the engine rpm increases when the air control valve hose is released.
FLUID LEVEL CHECK
SR0G0±03
1. KEEP VEHICLE LEVEL
2. BOOST FLUID TEMPERATUREWith the engine idling at 1,000 rpm or less, turn the steering
wheel from lock to lock several times to boost fluid tempera-
ture.
Fluid temperature:
805C (176 5F)
3. STOP ENGINE
4. CHECK FOR FOAMING OR EMULSIFICATION
HINT: Foaming and emulsification indicate either the exis-
tence of air in the system or that the fluid level is too low.
5. CHECK FLUID LEVEL IN OIL RESERVOIR Check the fluid level and add fluid if necessary.
Fluid:
ATF DEXRON
[ II
HINT: Check that the fluid level is within the HOT LEVEL of
the dipstick of the reservoir cap. If the fluid is cold, check that
it is within the COLD LEVEL of the dipstick.
±
STEERING POWER STEERINGSR±113
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POWER STEERING SYSTEM BLEEDING
SR0G2±04
1. CHECK FLUID LEVEL IN OIL RESERVOIRCheck the fluid level and add fluid if necessary.
Fluid:
ATF DEXRON
[ II
HINT: Check that the fluid level is within the HOT LEVEL of
the dipstick of the reservoir cap. If the fluid is cold, check that
it is within the COLD LEVEL of the dipstick.
2. START ENGINE AND TURN STEERING WHEEL FROM LOCK TO LOCK 3 OR 4 TIMES
With the engine speed below 1,000 rpm, turn the steering
wheel to left or right full lock and keep it there for 2±3 se-
conds, then turn the wheel to the opposite full lock and keep
it there for 2±3 seconds.
3. CHECK THAT FLUID IN OIL RESERVOIR IS NOT FOAMY OR CLOUDY AND DOES NOT RISE OVER MAXIMUM
WHEN ENGINE IS STOPPED
Measure the fluid level with the engine running. Stop the en-
gine and measure the fluid level.
Maximum rise:
5 mm (0.20 in.)
If a problem is found, repeat fluid replacement on page
SR±114. Rep air the PS if the problem persists.
OIL PRESSURE CHECK
SR0G3±03
1. CONNECT PRESSURE GAUGE
(a) Using SST, disconnect the pressure line joint.SC 400:
SST 09631±22020
±
STEERING POWER STEERINGSR±115
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(b) Connect the gauge side of the pressure gauge to the PSpump side, and the valve side to the gear housing side.
2. BLEED POWER STEERING SYSTEM (See page SR±115)
3. START ENGINE AND RUN IT AT IDLE
4. BOOST FLUID TEMPERATURE With the engine idling at 1,000 rpm or less, turn the steering
wheel from lock to lock several times to boost fluid tempera-
ture.
Fluid temperature: 80
C (176
F)
5. CHECK FLUID PRESSURE READING WITH VALVE
CLOSED
Close the pressure gauge valve and observe the reading on
the gauge.
Minimum pressure:
7,355 kPa (75 kgf/cm
2, 1,067 psi)
NOTICE:
w Do not keep the valve closed for more than 10 seconds.
w Do not let the fluid temperature become too high.
If pressure is low, repair or replace the PS vane pump.
6. OPEN VALVE FULLY
7. CHECK AND RECORD PRESSURE READING AT 1,000
RPM
8. CHECK AND RECORD PRESSURE READING AT 3,000 RPM
Check that the pressure difference between the 1,000 rpm
and 3,000 rpm checks is less than 490 kPa (5 kgf/cm
2, 71
psi). If the difference is excessive, repair or replace the flow
control valve of the PS vane pump.
NOTICE: Do not operate the steering wheel.
SR±116±
STEERING POWER STEERING
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9. CHECK PRESSURE READING WITH STEERING WHEELTURNED TO FULL LOCK
Be sure the pressure gauge valve is fully opened and the en-
gine idling.
Minimum pressure:
7,355 kPa (75 kgf/cm
2, 1,067 psi)
NOTICE:
w Do not maintain lock position for more than 10 seconds.
w Do not let the fluid temperature become too high.
If pressure is low, the gear housing has an internal leak and
must be repaired or replaced.
10. MEASURE STEERING EFFORT
(a) Center the steering wheel and run the engine at idle.
(b) Using a spring scale, measure the steering effort in both directions.
Maximum steering effort:
40 N (4.1 kgf, 9.0 lbf)
If steering effort is excessive, repair the power steering unit.
HINT: Be sure to consider the tire type, pressure and contact
surface before making your diagnosis.
(c) Disconnect the solenoid connector.
(d) Using a spring scale, measure the steering effort in both directions.
(Reference)
Maximum steering effort:
76 N (7.7 kgf, 17.0 lbf)
If steering effort is not heavier than (b), check solenoid.
HINT: Be sure to consider the tire type, pressure and contact
surface before making your diagnosis.
±
STEERING POWER STEERINGSR±117
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