shock LEXUS SC300 1991 Service User Guide

(c) Check for abnormal noise during acceleration anddeceleration, and for shock at up±shift and down±shift.
3. L POSITION TEST Shift into the 2 position and fully depress the accelerator ped-
al and check the following points:
(a) Check no up±shift While running in the L position, check to see that there is no
up±shift to 2nd gear.
(b) Check engine braking While running in the L position, release the accelerator pedal
and check the engine braking effect.
(c) C h e c k f o r a bnormal noise during acceleration and
deceleration.
4. R POSITION TEST Shift into the R position and fully depress the accelerator ped-
al and check for slipping.
CAUTION: Before conducting this test ensure that the test area
is free from personnel and obstructor.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±43
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TIME LAG TEST
When the shift lever is shifted while the engine is idling, there will be a \
certain time lapse or lag before the
shock can be felt. This is used for checking the condition of the O/D direct \
clutch, forward clutch, direct
clutch, and first and reverse brake.
NOTICE:
Perform the test at normal operating fluid temperature 50±80 C (122±176 F).
 Be sure to allow a one minute interval between tests.
 Make 3 measurements and take the average value.
MEASURE TIME LAG
(a) Fully apply the parking brake
(b) Start the engine and check idle speed.
Idle speed:
650 RPM (In N position and air conditioner OFF)
(c) Shift the shift lever from N to D position. Using a stop watch, measure the time it take\
s from shifting thelever until the shock is felt.
In same manner, measure the time lag for N
R.
Time lag:
N D Less than 1.2 seconds
N R Less than 1.5 seconds
AT±52±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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DESCRIPTION
GENERAL DESCRIPTION
AT0GE±02
The A340E automatic transmission is a 4±speed Electronically Controlled \
Transmission with an intelligent
control like the A341E automatic transmission used in the LS400. The A34\
0E automatic transmission has
the following features.

When shifting, engine torque is controlled and the clutch hydraulic pressure\
in the transmission is
electronically controlled to reduce transmission shift shock.

A new type of ATF (ATF Type T±II) is used which provides improved shifting characteristics a\
nd
prevents deterioration in the ATF over time.
HINT: For the A340E automatic transmission, use ATF Type T±II or equivalent.

A super flow torque converter clutch is used to improve the transmission\
efficiency.
The A340E automatic transmission is mainly composed of a torque converter c\
lutch with lock±up clutch,
4±speed planetary gear unit, hydraulic control system and the electro\
nic control system.
To minimize the possibility of incorrect operation of the automatic transm\
ission, a shift lock mechanism has
also been added.
AT±2
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION DESCRIPTION
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2. HYDRAULIC CONTROL SYSTEMThe hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accumu-
lators, the clutches and brakes, as well as the fluid passages which connect al\
l of these components.
Based on the hydraulic pressure created by the oil pump, the hydraulic control system governs the hydrau-
lic pressure acting on the torque converter clutch, clutches and brakes \
in accordance with the vehicle driv-
ing conditions.
There are 4 solenoid valves on the valve body.
The No.1 and No.2 solenoid valves are turned on and off by signals from the ECM to operate the shift
valves, and change the gear shift position.
The No.3 solenoid valve is operated by signals from the ECM to engage or di\
sengage the lock±up clutch
of the torque converter clutch.
The No.4 solenoid valve is operated by signals from the ECM to control the \
engagement speed and reduce
gear shift shock.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION OPERATIONAT±7
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3. ELECTRONIC CONTROL SYSTEMThe electronic control system for the A340E automatic transmission provides\
extremely precise control of
the gear shift timing and lock±up timing in response to driving conditio\
ns as sensed by various sensors
located throughout the vehicle and in response to the engine's running condition.
At the same time, the ECM control reduces vehicle squat when the vehicle s\
tarts out and gear shift shock.
The electronic control system is also equipped with a self diagnosis sys\
tem which diagnoses malfunctions
of electronically controlled components and warns the driver, and a fail±safe system which makes it pos-
sible for the vehicle to continue functioning when a malfunction occurs.
CONSTRUCTION The electronic control system can be broadly divided onto 3 groups; the \
sensors, ECM and actuators.
AT±8±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION OPERATION
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HOW TO PROCEED WITH TROUBLESHOOTING
AT09N±0D
1. CUSTOMER PROBLEM ANALYSISUsing the customer problem analysis check sheet for reference, ask the c\
ustomer in as much detail as
possible about the problem.
2. CHECK AND CLEAR THE DIAGNOSTIC TROUBLE CODES (PRECHECK) Before confirming the problem symptom, first check if there are any diagnostic\
trouble malfunction codes
stored in memory. When there are malfunction codes, make a note of them, then clear them\
and proceed
to ª3. Problem Symptom Confirmationº.
3. PROBLEM SYMPTOM CONFIRMATION Confirm the problem symptoms.
4. SYMPTOM SIMULATION If the problem does not reappear, be sure to simulate the problem by mainly checking the circuits indica\
ted
by the diagnostic trouble code in step 2., using ªProblem Simulation me\
thodº.
5. DIAGNOSTIC TROUBLE CODE CHECK Check the diagnostic trouble codes. Check if there is abnormality in the\
sensors or the wire harness.
If a malfunction code is output, proceed to ª6. Diagnostic Trouble Code Chartº.
If the normal code is output, proceed to ª11. Matrix Chart of Problem Symptomsº.
Be sure to proceed to ª6. Diagnostic Trouble Code Chartº after the steps 2. and 3. are completed.
If troubleshooting is attempted only by following the malfunction code sto\
red in the memory is output, errors
could be made in the diagnosis.
6. DIAGNOSTIC TROUBLE CODE CHART If a malfunction code is confirmed in the diagnostic trouble code check, p\
roceed to the inspection proce-
dure indicated by the matrix chart for each diagnostic trouble code.
7. PRELIMINARY CHECK Carry out a preliminary check of the transmission oil level, throttle ca\
ble adjustment, etc.
8. SHIFT POSITION SIGNAL CHECK
Carry out the shift position signal check when the transmission gears do\
not up±shift, down±shift or lock±
up. This is to check the output condition from the ECM to each solenoid. If the r\
esults are NG, then it is
likely that the trouble is in the electrical system (particularly in th\
e sensors or the ECM).
Proceed to Part 1 (Electrical System) under ª11. Matrix Chart of Problem Symptomsº. If all the circuits speci-
fied in Part 1 are OK, check the ECM and replace it.
9. MECHANICAL SYSTEM TEST (Stall Test, Time Lag Test, Line Pressure Test, Accumulator Back Pressure Test)
If the malfunction is found in the stall test, time lag test, line press\
ure test or accumulator back pressure
test, check the parts indicated in the respective tests. If the problem is th\
at ªshift shock is largeº, perform
the accumulator back pressure test.
10. MANUAL SHIFTING TEST If the results of the manual driving test are NG, it is likely that the trouble is in the mechanical system or
hydraulic system. Proceed to Part 2 (Mechanical System) under the Matrix Chart \
of Problem Symptoms.
AT±32
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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REMOVAL OF FRONT FENDER
(See page BO±92)
1. REMOVE FRONT BUMPER (See page BO±91)
2. REMOVE FRONT FENDER WHEEL OPENING MOULDING
(See page BO±102)
3. REMOVE FENDER LINER (a) Remove eight screws.
(b) Remove the liner with four clips.
4. REMOVE FRONT FENDER Remove eleven bolts and the fender.
CAUTION: Do not damage or shock the front airbag
sensor at all.
INSTALLATION OF FRONT FENDER
(See page BO±91)
1. INSTALL FRONT FENDER Install eleven bolts and the fender.
BO±92
±
BODY Front Fender
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BODY DIMENSIONS
Description
1. BASIC DIMENSIONS(a) There are two types of dimensions in the diagram. (Three±dimensional distance)
wStraight±line distance between the centers of two
measuring points.
(Two±dimensional distance)
wHorizontal distance in forward/rearward between the centers of two measuring points.
wThe height from an imaginary standard line.
(b) In cases in which only one dimension is given, left and right are symmetrical.
(c) The dimensions in the following drawing indicate actual
distance. Therefore, please use the dimensions as a
reference.
2. MEASURING (a) Basically, all measurements are to be done with atracking gauge. For portions where it is not possible to
use a tracking gauge, a tape measure should be used.
(b) Use only a tracking gauge that has no looseness in the body, measuring plate, or pointers.
HINT:
1. The height of the left and right pointers must be equal.
2. Always calibrate the tracking gauge before measuring or after adjusting the pointer height.
3. Take care not to drop the tracking gauge or otherwise shock it.
4. Confirm that the pointers are securely in the holes.
(c) When using a tape measure, avoid twists and bends in
the tape.
(d) When tracking a diagonal measurement from the front
spring support inner hole to the suspension member
upper rear installation hole, measure along the front
spring support panel surface.
±
BODY Body Dimensions (Description)BO±127
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SRS AIRBAG
(See page AB±2)
The LEXUS SC300 is equipped with an SRS (Supplemental Restraint System)\
airbag.
Failure to carry out service operations in the correct sequence could cause the airbag system to deploy,
possibly leading to a serious accident.
When removal or installation of airbag parts and the yellow wire harness\
and connector for the airbag is
necessary, refer to the precautionary notices in the AB section before performing\
the operation.

Work must be started after 20 seconds or longer from the time the ignition switch is set to the LOCK
position and the negative (±) terminal cable is disconnected from the batte\
ry.
(The airbag system is equipped with a back±up power source so that if wor\
k is started within 20 se-
conds of disconnecting the negative (±) terminal cable of the batte\
ry, the airbag may be deployed.

To avoid erasing the memory of each memory system, never use a back±up power supply from
outside the vehicle.

Before repairs, remove the airbag sensors if shocks are likely to be applied t\
o the sensors during
repaires.

The front airbag sensor set bolt has been anti±rust treated. When the\
sensor is removed, always
replace the set bolt with a new one.

If the front airbag sensors, center airbag sensor or steering wheel pad ha\
ve been dropped, or if there
are cracks, dents or other defects in the case, bracket or connector, replace them with new ones.

Never use airbag parts from another vehicle. When replacing parts, repla\
ce them with new parts.

Do not expose the front airbag sensors, center airbag sensor or steering w\
heel pad directly to hot air
or flames.

The airbag system's wire harness is integrated with the cowl wire harness assembly. The wires for the
airbag wire harness are encased in a yellow corrugated tube. All the connector\
s for the system are
also a standard yellow color. If the airbag system wire harness becomes disconnected or the
connector becomes broken due to an accident, etc., repair or replace it as shown \
on page AB±20.

The steering wheel must be fitted correctly to the steering column with the\
spiral cable at the neutral
position; otherwise, cable disconnection and other troubles may result. \
Refer to page AB±14 of this
manual concerning correct steering wheel installation.

When removing the steering wheel pad or handling a new steering wheel pad, i\
t 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. (\
Storing the
pad with its metallic surface up may lead to a serious accident if the a\
irbag inflates for some reason.)

Grease should not be applied to the steering wheel pad and the pad should not \
be cleaned with
detergents of any kind.

Store the steering wheel pad where the ambient temperature remains below 93 C (200 F), without
high humidity and away from electrical noise.

Information labels are attached to the periphery of the airbag component\
s. Follow the notices.

When the ignition switch is at ACC or ON and the airbag warning light remains on, the cent\
er airbag
sensor assembly has detected a malfunction code. (See page AB±30).
BO±8
±
BODY General Information
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\
 \

Problem No.
 \
 \
Radio not operating when power switch turned to ºONº 1
 


\
 
\

\

Display indicates when power switch turned to ºONº, but no sound (\
including ºnoiseº)
is produced (except woofer). 


2
 \
 \
Noise present, but AM±FM not operating 3
 
Radio
\
 \
Any speaker does not work (except woofer). 4
 Radio\
 \
Volume faint (except woofer). 5 \
 \
Woofer does not work. 6 


\
 
\

\
Woofer volume faint. 

7
 \
 \
Reception poor. 8
 \
 \
Preset memory disappears. 9
 \
 \
Volume remains at maximum level. 10
 \
 \
Cassette tape cannot be inserted. 11
 \
 \
Cassette tape will not eject. 12
 \
 \
Display indicates, but no sound is produced (except woofer). 13 \
 \
Any speaker does not work (except woofer). 14 

Tape player
\
 
\

\
Volume faint (except woofer). 

15
 \
 \
Woofer does not work. 16
 \
 \
Woofer volume faint. 17
 \
 \
Sound quality poor. 18
 \
 \
Volume remains at maximum level. 19
 \
 \
Magazine cannot be inserted into auto changer. 20
 \
 \
Magazine is inserted, but display does not indicate ºCDº. 21 \
 \
Display indicates, but no sound is produced (except woofer). 22 


\
 
\

\
Any speaker does not work (except woofer). 

23
 CDplayer\
 \
Volume faint (except woofer). 24
 CD player\
 \
RH channel or LH channel speaker volume faint. 25
 \
 \
Woofer does not work. 26
 \
 \
Woofer volume faint. 27
 \
 \
Sound quality poor. 28
 \
 \
Volume remains at maximum level. 29 
Noise
\
 \
Noise produced by vibration or shock while driving. 30 


Noise\
 
\

\
Noise produced when engine starts. 

31
 Antenna\
 \
Antenna±related. 32
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±219
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