1991 LEXUS SC300 mirror

DESCRIPTION
By operating the driving position memory and return switch the driver's seat, steering wheel and outer mir-
ror are moved to their respective memorized positions.
 

Parts Name\
 
\

\
Function 




Tilt & Telescopic ECU
\
 
\


\

\

Control the manual operation, return operation and memory and return ope\
ration for tilt
and telescopic of steering wheel.
 Auto Set Switch\
 \
This switch is a main switch for the away operation of tilt and telescop\
ic.
 




Manual Switch\
 
\


\

\

This switch is an operation switch to operate tilt and telescopic manual\
ly. When one of tilt
up, tilt down, telescopic Extension and telescopic Contraction is operat\
ed, steering wheel
will be able to set on the optional position within the extent of operat\
ing.
 


Driving Position
Memory and
Return Switch\
 
\

\

Operating this switch makes return operation that driver seat steering w\
heel and outer mirror
are set on the memorized position working together power seat and outer \
mirror.
 

Position Sensor
\
 
\

\
Tilt position sensor detect an amount of tilt and input it to ECU.
Telescopic position sensor detect an amount of slide and input it to ECU.\
 

Motor
\
 
\

\
There is a tilt motor and telescopic motor respectively. These are operated by a signal from
the ECU.
SR±40±
STEERING STEERING COLUMN
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HOW TO PROCEED WITH TROUBLESHOOTING
Perform troubleshooting in accordance with the procedure on the following page.\

CUSTOMER PROBLEM ANALYSIS
Using the customer problem analysis check sheet for reference, obtain as much detail as possible about
the problem.
 PROBLEM SYMPTOM CONFIRMATION,  SYMPTOM SIMULATION
Confirm the problem symptoms. If the problem does not reappear, be sure to simulate the problem, using
the ªProblem Simulation Methodsº.
 MATRIX CHART OF PROBLEM SYMPTOMS
Confirm the order of inspection for each applicable problem symptom on t\
he matrix chart after first fully
confirming the scope of the problem symptoms. For example, if the tilt operation i\
s not working, check
whether the tilt is not working in manual, auto and return, and also check if the telescopic, seat or mirror
operation is not working in addition to the tilt operation.
 CIRCUIT INSPECTION
Proceed with diagnosis of each circuit in accordance with the inspection order \
confirmed in . Judge
whether the cause of the problem is in the sensor, actuators, wire harness and connectors, or the ECU.
6 REPAIR
After the cause of the problem is located, perform repairs by following the i\
nspection and replacement pro-
cedures in this manual.
7 CONFIRMATION TEST After completing repairs, confirm not only that the malfunction is eliminated,\
but also seat and mirror opera-
tions are normal.
SR±45
SR±52
SR±62 ~ SR±101 IN±26
SR±44
±
STEERING STEERING COLUMN
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GENERAL DESCRIPTION
The LEXUS SC400/300 is equipped with an SRS (Supplemental Restraint System\
) such as the driver
airbag and front passenger airbag. Failure to carry out service operations in \
the correct sequence
could cause the SRS to unexpectedly deployed during servicing, possibly leadin\
g to a serious acci-
dent. Further, if a mistake is made in servicing the supplemental restraint system, i\
t is possible the
SRS may fail to operate when required. Before performing servicing (inc\
luding removal or installa-
tion of parts, inspection or replacement), be sure to read the followin\
g items carefully, then follow
the correct procedure described in the repair manual.
1. Malfunction symptoms of the supplemental restraint system are difficult to confirm, so the diagnostic trouble codes become the most important source of information when troubleshooting. When
troubleshooting the supplemental restraint system, always inspect the diagnostic trouble codes before
disconnecting the battery (See page RS±59).
2. Work must be started after 90 seconds from the time the ignition switch turn\
ed to the LOCK position
and the negative (±) terminal cable is disconnected from the battery. (The supplemental restraint
system is equipped with a back±up power source so that if work is sta\
rted within 90 seconds of
disconnecting the negative (±) terminal cable of the battery, the SRS may be deployed.)
When the negative (±) terminal cable is disconnected from the battery, memory of the clock and audio sys-
tems will be canceled. So before starting work, make a record of the contents memo\
rized by the audio
memory system. When work is finished, reset the audio systems as before and ad\
just the clock. When the
vehicle has power tilt and power telescopic steering, 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 work is finished, it will be necessary\
to explain this fact to the custom-
er, 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 SRS does not deploy, the steering wheel pad, front passenger
airbag assembly, front airbag sensors and center airbag sensor assembly should be inspe\
cted (See pages
RS±16 , 28 , 41 and 44).
4. Never use SRS parts from another vehicle. When replacing parts, replace \
them with new parts.
5. Before repairs, remove the airbag sensor if shocks are likely to be applied to the sensors during r\
epairs.
6. Never disassemble and repair the steering wheel pad, front passenger airbag a\
ssembly, front airbag sensors or center airbag sensor assembly in order to reuse it.
7. If the steering wheel pad, front passenger airbag assembly, front airbag sensors or center airbag sensor assembly have been dropped, or if there are cracks, dents or dents or ot\
her defects in the case, bracket
or connector, replace them with new ones.
8. Do not expose the steering wheel pad, front passenger airbag assembly, front airbag sensors and center airbag sensor assembly directly to hot air or flames.
9. Use a volt/ohmmeter with high impedance (10 k
/V minimum) of troubleshooting of the system's electrical
circuit.
10. Information labels are attached to the periphery of the SRS components. \
Follow the instructions on the
notices.
11. After work on the supplemental restraint system is completed, perform the SRS\
warning light check (See page RS±59 ).
12. If the vehicle is equipped with a mobile communication system, refer to \
the precaution in the IN section. RS±2
±
SUPPLEMENTAL RESTRAINT SYSTEM GENERAL DESCRIPTION
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Diag. Code 31Air Flow Meter Circuit
CIRCUIT DESCRIPTION
As shown in the figure at right, when a pillar (Vortex
generating body) is placed in the path of a uniform flow,
vortices called Karman±Vortex are generated down-
stream of the object. Using this principle, a vortex gen-
erator is placed inside the air flow meter. By measuring
the frequency of the vortices generated, the ECU can
determine the volume of air flowing through the air flow
meter. The vortices are detected by their exerting pres-
sure on thin metal foil (mirror) surfaces and a light emit-
ting element and light receptor (LED and photo transis-
tor) positioned opposite the mirror which senses the
vibrations in the mirror optically. The ECU uses these
signals mainly for calculation of the basic injection vol-
ume and the basic ignition advance angle.
If the ECU records diagnostic code º31º, it enters fail safe mode \
(See page TR±22).
TR±88
±
ENGINE TROUBLESHOOTING Circuit Inspection
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Diag. Code 31Air Flow Meter Circuit
CIRCUIT DESCRIPTION
As shown in the figure at right, when a pillar (Vortex
generating body) is placed in the path of a uniform flow,
vortices called Karman±Vortex are generated down-
stream of the object. Using this principle, a vortex gen-
erator is placed inside the air flow meter. By measuring
the frequency of the vortices generated, the ECU can
determine the volume of air flowing through the air flow
meter. The vortices are detected by their exerting pres-
sure on thin metal foil (mirror) surfaces and a light emit-
ting element and light receptor (LED and photo transis-
tor) positioned opposite the mirror which senses the
vibrations in the mirror optically. The ECU uses these
signals mainly for calculation of the basic injection vol-
ume and the basic ignition advance angle.
If the ECU records diagnostic code º31º, it enters fail safe mode \
(See page TR±22).
TR±88
±
ENGINE TROUBLESHOOTING Circuit Inspection
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QTY
PART NUMBER
PART NAME
CHANGE IN SUPPLY PARTS FOR INNER REAR VIEW MIRROR Page 1 of 3
Supply parts for the inner rear view mirror have been changed from an assembly to the com-
ponents listed below.
PART NUMBER INFORMATION:
BODY
BO92±008
DECEMBER 4, 1992
SC 300/400
87825±24010 1Spring, Inner Rear View Mirror Body Setting
DESCRIPTION
87808±24010 2Holder Subassembly,
Inner Rear View Mirror
87817±24010 1Spacer, Inner Rear View Mirror
N/A N/A Not available as a
separate supply part
This part is attached to windshield. Use original part or replace windshield\
and mirror base
as an assembly, if necessary.
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CHANGE IN SUPPLY PARTS FOR INNER REAR VIEW MIRROR (CONT'D)Page 2 of 3
1) Remove Center Visor
a) Remove the visor arm set clip (Figure 1).
b) Remove the two attachment screws.
Figure 1
Figure 2
Figure 3
Figure 4 2) Remove Inner Rear View Mirror
a) Remove mirror set screw (Figure 2).
b) Disconnect the mirror wire harness.
INNER REAR VIEW MIRROR REMOVAL:
Note: To prevent damage to plastic parts,
tape the screwdriver tip before use.
COMPONENT DISASSEMBLY:
a) Using snap ring pliers, remove the spring.
b) Remove the two holders and the spacer (Figure 3).
NOTE: Do not remove the mirror base from the windshield.
COMPONENT ASSEMBLY:
a) Reinstall components by installing the spacer, two holders and spring.
b) Install the spring using snap ring pliers (Figure 4).
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CHANGE IN SUPPLY PARTS FOR INNER REAR VIEW MIRROR (CONT'D)Page 3 of 3
a) Install inner rear view mirror by re±installing
attachment set screw (Figure 5).
INNER REAR VIEW MIRROR & CENTER
VISOR INSTALLATION:
PARTS LOCATION:
Note: Use thread locking compound on
set screw to ensure screw reten-
tion.
b) Re±connect wire harness.
Note: Check review mirror dimming operation before re±installation of
center visor.
c) Install center visor by re±installing two attachment screws.
d) Re±install visor arm set clip.
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