ect LEXUS SC300 1991 Service Repair Manual

ABBREVIATIONS USED IN THIS
MANUAL
ABS Anti±Lock Brake System J/B Junction Block
A/C Air Conditioner LED Light Emitting Diode
ALR Automatic Locking Retractor LH Left±Hand
APPROX. Approximation LHD Left±Hand Drive
A/T, ATM Automatic Transmission LLC Long Life Coolant (Year Around Coolant)
ATF Automatic Transmission Fluid Max. Maximum
BTDC Before Top Dead Center Min. Minimum
BVSV Bimetal Vacuum Switching Valve MP Multipurpose
CALIF. Vehicles Sold in California N Neutral
CB Circuit Breaker OD, O/D Overdrive
DOHC Double Over Head Cam O/S Oversize
DP Dash Pot P & BV Proportioning and Bypass Valve
ECT Electronic Controlled Transmission PCV Positive Crankcase Ventilation
ECU Electronic Controlled Unit PS Power Steering
EFI Electronic Fuel Injection RH Right±Hand
EGR Exhaust Gas Recirculation RL Rear Left
ELR Emergency Locking Retractor RR Rear Right
EPR Evaporator Pressure Regulator RR, Rr Rear
ESA Electronic Spark Advance SRS Supplemental Restraint System
EVAP Evaporative (Emission Control) SSM Special Service Materials
EX Exhaust (manifold, valve) SST Special Service Tools
Ex. Except STD Standard
FIPG Formed in Place Gasket SW Switch
FL Front Left TDC Top Dead Center
FL Fusible Link TDCL Total Diagnostic Communication Link
FPU Fuel Pressure Up Temp. Temperature
FR Front Right TRAC Traction Control System
FR, Fr Front TWC Three±Way Catalyst
HAC High Altitude Compensation VSV Vacuum Switching Valve
IG Ignition VTV Vacuum Transmitting Valve
IN Intake (manifold, valve) w/ With
INT Intermittent w/o Without
ISC Idle Speed Control
IN±34±
INTRODUCTION Abbreviations Used in This Manual
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HOW TO USE THIS MANUAL
INDEX
An INDEX is provided on the first page of each sec-
tion to guide you to the item to be repaired.
To assist you in finding your way through the manual,
the Section Title and major heading are given at the
top of every page.
ALPHABETICAL INDEX
An ALPHABETICAL INDEX is also provided at the
end of this manual so that you can rapidly find the
item and page you are searching for.
GENERAL DESCRIPTION
At the beginning of each section, a General Descrip-
tion (Precautions) is given that pertains to all repair
operations contained in that section.
Read these precautions before starting any
repair task.
REPAIR PROCEDURES
Most repair operations begin with an overview il-
lustration. It identifies the components and shows
how the parts fit together.
Example:
PREPARATION
Preparation lists the SST (Special Service Tools), rec-
ommended tools, equipment, lubricant and SSM
(Special Service Materials) which should be prepared
before beginning the operation and explains the pur-
pose of each one.
TROUBLESHOOTING
TROUBLESHOOTING tables are included for each
system to help you diagnose the problem and find the
cause.
The fundamentals of how to proceed with trouble±
shooting are described on page IN±15. Be sure to
read this before performing troubleshooting.
IN±2
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The procedures are presented in a step±by±step format:
wThe illustration shows what to do and where to do it.
w The task heading tells what to do.
w The detailed text tells how to perform the task and gives
other information such as specifications and warnings.
Example:
This format provides the experienced technician with a FAST
TRACK to the information needed. The upper case task
heading can be read at a glance when necessary, and the
text below it provides detailed information. Important specifi-
cations and warnings always stand out in bold type.
REFERENCES
References have been kept to a minimum. However, when
they are required you are given the page to refer to.
SPECIFICATIONS
Specifications are presented in bold type throughout the text
where needed. You never have to leave the procedure to look
up your specifications. They are also found at the end of each
section, for quick reference.
CAUTIONS, NOTICES, HINTS:
w CAUTIONS are presented in bold type, and indicate
there is a possibility of injury to you or other people.
w NOTICES are also presented in bold type, and indicate
the possibility of damage to the com ponent being
repaired.
w HINTS are separated from the text but do not appear in
bold. They provide additional information to help you
efficiently perform the repair.
SI UNIT
The UNIT given in this manual are primarily expressed with
the SI UNIT (International System of Unit), and alternately ex-
pressed in the metric system and in the yard/pound system.
Example:
Torque: 30 N Vm (310 kgf Vcm, 22 ft Vlbf)
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IDENTIFICATION INFORMATION
VEHICLE IDENTIFICATION NUMBER
This number is stamped on the vehicle identification number plate
at the top of the left instrument panel and is also on the certification
regulation label.A: Vehicle Identification Number
B: Vehicle Identification Number Plate
C: Certification Regulation Label
ENGINE SERIAL NUMBER
The engine serial number is stamped on the engine block as
shown.
GENERAL REPAIR INSTRUCTIONS
1. Use fender seat and floor covers to keep the vehicle clean
and prevent damage.
2. During disassembly, keep parts in the appropriate order to facilitate reassembly.
3. Observe the following:
(a) CAUTION: W ork 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
disconnected from the battery (See page AB±2).
(b) B e fo re pe rfo rmin g ele ctrica l wo rk, disc onnect the
negative cable from the battery terminal.
(c) If it is necessary to disconnect the battery for inspection or repair, always disconnect the cable from the negative
(±) terminal which is grounded to the vehicle body.
(d) To prevent damage to the battery terminal post, loosen the terminal nut and raise the cable straight up without
twisting or prying it.
(e) Clean the battery terminal posts and cable terminals with a shop rag. Do not scrape them with a file or other
abrasive object.
(f) Install the cable terminal to the battery post with the nut loose, and tighten the nut after installation. Do not use
a hammer to tap the terminal onto the post.
(g) Be sure the covers for the positive (+) terminal and negative (±) terminal are properly in place.
4. Check hose and wiring connectors to make sure that they are
secure and correct.
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5. Non±reusable parts(a) Always replace cotter pins, gaskets, O±rings and oilseals etc. with new ones.
(b) Non±reusable parts are indicated in the component
illustrations by the º º symbol.
6. Precoated parts Precoated parts are bolts and nuts, etc. that are coated with
a seal lock adhesive at the factory.
(a) If a precoated part is retightened, loosened or causedto move in any way, it must be recoated with the
specified adhesive.
(b) Recoating of precoated parts
(1) Clean off the old adhesive from the bolt, nut or threads.
(2) Dry with compressed air.
(3) Apply the specified seal lock adhesive to the bolt or nut threads.
(c) P re co a te d pa rts are in d ica te d in th e co m ponent
illustrations by the º
º symbol.
7. When necessary, use a sealer on gaskets to prevent leaks.
8. Carefully observe all specifications for bolt tightening
torques. Always use a torque wrench.
9. Use of special service tools (SST) and special service materials (SSM) may be required, depending on the nature
of the repair. Be sure to use SST and SSM where specified
and follow the proper work procedure. A list of SST and SSM
can be found in the preparation part at the front of each
section in this manual.
10. When replacing fuses, be sure the new fuse has the correct
amperage rating. DO NOT exceed the rating or use one with
a lower rating.
11. Care must be taken when jacking up and supporting the vehicle. Be sure to lift and support the vehicle at the proper
locations (See page IN±33).
(a) If the vehicle is to be jacked up only at the front or rear end, be sure to block the wheels at the opposite end in
order to ensure safety.
(b) After the vehicle is jacked up, be sure to support it on
stands. It is extremely dangerous to do any work on a
vehicle raised on a jack alone, even for a small job that
can be finished quickly.
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12. Observe the following precautions to avoid damage to theparts:
(a) Do not open the cover or case of the ECU unless
absolutely necessary (If the IC terminals are touched, the
IC may be destroyed by static electricity.).
(b) To pull apart electrical connectors, pull on the connectoritself, not the wires (See page BE±2).
(c) Be careful not to drop electrical components, such as sensors or relays. It they are dropped on a hard floor,
they should be replaced and not reused.
(d) When checking continuity at the wire connector, insert the tester probe carefully to prevent terminals from
bending.
(e) To disconnect vacuum hoses, pull on the end, not the middle of the hose.
(f) When steam cleaning an engine, protect the distributor,
coil and air filter from water.
(g) Ne ve r use an imp a ct wre n ch to re mo ve or in sta ll temperature switches or temperature sensors.
(h) When using a vacuum gauge, never force the hose onto
a connector that is too large. Use a step±down adapter
instead. Once the hose has been stretched, it may leak.
13. Tag hoses before disconnecting them: (a) When disconnecting vacuum hoses, use tags to identify
how they should be reconnected.
(b) After completing a job, double check that the vacuum hoses are properly connected. A label under the hood
shows the proper layout.
14. Installation of wheels The wheel assemblies are of the uni±directional type and
must be rotated only between the front and rear as illustrated.
Wheels are marked with turning direction indicators.
When installing the wheels, check the marks carefully and
install the wheel correctly.
15. Bleeding of traction control system When repairing the brake master cylinder or TRAC system,
bleed the air out of the TRAC system (See page BR±7).
CAUTION: Since the fluid is under high pressure, it could
spray out with great force, so be careful.
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TOTAL DIAGNOSTIC
COMMUNICATION LINK (TDCL)
The TDCL is provided inside the cabin (located under the left side
instrument panel) as a connector exclusively for diagnosis of data
from the engine, ECT, ABS, A/C, Airbag and Cruise Control Sys-
tem to improve serviceability. The check connector inside the en-
gine compartment is used for engine adjustment.
Connecting the following terminals of the TDCL to terminal E1 se-
lects the diagnosis mode shown.
NOTICE: Never make a mistake with the terminal connection
position as this will cause a malfunction.
TerminalSystem
TE1Engine and ECT (Normal mode)
TE2 and TE1Engine and ECT (Test mode)
TcABS, A/C, Airbag, Traction Control and Cruise
Control System
TTECT
Refer to the respective system for the inspection method.
HINT: By connecting the TDCL up to a monitor specifically de-
signed for use with the TDCL, the diagnosis result for each system
can be read easily.
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INTRODUCTION Total Diagnostic Communication Link (TDCL)IN±7
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PRECAUTIONS FOR VEHICLES
EQUIPPED WITH SRS AIRBAG
The LEXUS SC400 is equipped with an SRS (Supplemental Re-
straint System) airbag.
Failure to carry out service operations in the correct sequence
could cause the airbag system to unexpectedly deploy during serv-
icing, possibly leading to a serious accident.
Further, if a mistake is made in servicing the airbag system, it is pos-
sible the airbag may fail to operate when required.
Before performing servicing (including removal or installation of
parts, inspection or replacement), be sure to read the following
items carefully, then follow the correct procedure described in this
manual.
Locations of Airbag Components
1. Malfunction symptoms of the airbag system are difficult to confirm,
so the diagnostic codes become the most important source of
information when troubleshooting.
When troubleshooting the airbag system, always inspect the diag-
nostic codes before disconnecting the battery. (See page
AB±25)
2. Work must be started after approx. 20 seconds or longer from the time the ignition switch is turned to the LOCK position and
the negative (±) terminal cable is disconnected from the
battery.
(The airbag system is equipped with a back±up power source
so that if work is started within 20 seconds of disconnecting
the negative (±) terminal cable of the battery, the airbag may be
deployed.)
IN±8±
INTRODUCTION Precautions for Vehicles Equipped with SRS Airbag
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When the negative (±) terminal cable is disconnected from
the battery, memory of the clock and audio systems will be
cancelled. So before starting work, make a record of the con-
tents memorized by each memory system. Then when work
is finished, reset the clock and audio systems as before.
When the vehicle has power tilt and power telescopic steer-
ing, power seat, power outside rear view mirror and power
shoulder belt anchorage, which are all equipped with
memory function, it is not possible to make a record of the
memory contents. So when the operation is finished, it will be
necessary to explain this fact to the customer, and ask the
customer to adjust the features and reset the memory.
To avoid erasing the memory of each memory system, never
use a back±up power supply from outside the vehicle.
3. Even in cases of a minor collision where the airbag does not deploy, the front airbag sensors and the steering wheel pad
should be inspected. (See page AB±9)
4. Never use airbag parts from another vehicle. When replacing parts, replace them with new parts.
5. Before repairs, remove the airbag sensors if shocks are likely
to be applied to the sensors during repairs.
6. The center airbag sensor assembly contains mercury. After
performing replacement, do not destroy the old part. When
scrapping the vehicle or replacing the center airbag sensor
assembly itself, remove the center airbag sensor assembly
and dispose of it as toxic waste.
7. Never disassemble and repair the front airbag sensors, center airbag sensor assembly or steering wheel pad in order
to reuse it.
8. If the front airbag sensors, center airbag sensor assembly or steering wheel pad have been dropped, or if there are cracks,
dents or other defects in the case, bracket or connector,
replace them with new ones.
9. Do not expose the front airbag sensors, center airbag sensor assembly or steering wheel pad directly to hot air or flames.
10. U s e a v o l t / o h m m e t e r w i t h h i g h i m pedance (10 kW/V
minimum) for troubleshooting of the electrical circuit.
11. Information labels are attached to the periphery of the airbag components. Follow the notices.
12. After work on the airbag system is completed, perform the
airbag warning light check (See page AB±30).
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FRONT AIRBAG SENSOR
1. Never reuse the front airbag sensors involved in a collisionwhen the airbag has deployed. (Replace both the left and
right airbag sensors.)
2. Install the front airbag sensor with the arrow on the sensor facing toward the front of the vehicle.
3. The front airbag sensor set bolts have been anti±rust treated. When the sensor is removed, always replace the set bolts
with new ones.
4. The front airbag sensor is equipped with an electrical connection check mechanism. Be sure to lock this
mechanism securely when connecting the connector. If the
connector is not securely locked, a malfunction code will be
detected by the diagnosis system (See page AB±10).
SPIRAL CABLE (IN COMBINATION
SWITCH)
The steering wheel must be fitted correctly to the steering column
with the spiral cable at the neutral position; otherwise cable dis-
connection and other troubles may result. Refer to page AB±15
of this manual concerning correct steering wheel installation.
STEERING WHEEL PAD (WITH AIRBAG)
1. When removing the steering wheel pad or handling a new steering wheel pad, it should be placed with the pad top
surface facing up.
In this case, the twin±lock type connector lock lever should
be in the locked state and care should be taken to place it so
the connector will not be damaged. And do not store a steer-
ing wheel pad on top of another one. (Storing the pad with its
metallic surface up may lead to a serious accident if the air-
bag inflates for some reason.)
2. Never measure the resistance of the airbag squib. (This
may cause the airbag to deploy, which is very
dangerous.)
IN±10±
INTRODUCTION Precautions for Vehicles Equipped with SRS Airbag
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