LEXUS SC400 1991 Service Repair Manual
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ELECTRONIC CONTROL SYSTEM
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STEERING STEERING COLUMNSR±39
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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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PARTS LOCATION
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STEERING STEERING COLUMNSR±41
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STEERING STEERING COLUMN
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STEERING STEERING COLUMNSR±43
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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
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STEERING STEERING COLUMN
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CUSTOMER PROBLEM ANALYSIS
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WIRING DIAGRAM
TILT & TELESCOPIC ECU
SR±46±
STEERING STEERING COLUMN
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SC300 (M/T)
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STEERING STEERING COLUMNSR±47
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TERMINAL OF ECU
TILT & TELESCOPIC ECU
Terminal
No.
Symbol
Terminal Name
Terminal
No.
Symbol
Terminal Name
T9±1 Si Serial In T9±16 MSW Manual Switch
2 DSW Door Courtesy Switch 17 Vc Sensor Power Source
3 M1 Return Switch 1 18 ECU±B Power Source
4
ASW
Auto Switch
T10± 1
IG
Ignition Switch
5 E1 Sensor Ground 2 Te M+ Telescopic Contracted
6 Te S Telescopic Sensor 3 TiM± Tilt Down
7
TiS
Tilt Sensor
4
+B
Power Source
8
ECU±E
Ground
6
P
Park/Neutral Position Switch
9 So Serial Out 6 P Parking Brake Switch*
10 UWSW Unlock Warning Switch 7 GND Ground
11
MRY
Memory Switch
10
TiM+
Tilt Up
12 M2 Return Switch 2 11 TiM± Telescopic Extended
*
SC300 (M/T) Models
SR±48
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STEERING STEERING COLUMN
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