ect LEXUS SC300 1991 Service Repair Manual

OKNG
OKNG
WIRING DIAGRAM
3Check each limit switch.
C
OK
PDisconnect limit switch connector.
Check continuity of each terminal of limit switch.
Switch condition Condition Voltage
Slide neutral
limit switch
Reclining front
limit switch Reclining rear
limit switch ON
OFF ON
OFF
ON
OFF Seat is forward of the
neutral position.
Seat is to the rear of
the neutral position.
Seat back is fully reclined.
Others
Seat back is in the upright
position
Others Continuity
Open
Continuity
Continuity
Open
Open
Replace the limit switch.
4
Check for open and short in harness and connector between ECU and limit switc\
hes, limit
switches and SGND (See page IN±27).
Repair or replace harness or connector.
Check and replace ECU.
BE±342±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)
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WIRING DIAGRAM
Reclining Switch and Motor Circuit
CIRCUIT DESCRIPTION
When the power seat switch is turned to forward reclining, the seat back ret\
urns to upright.
When the switch is turned to rear reclining, the seat back reclines.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check power seat switch.
Check voltage between terminals B1 and
E1 of power seat switch.
NGCheck and repair harness and
connectors between battery and
power seat switch, power seat
switch and body ground.
NG
NG
OK
OK
OK
Check reclining motor.
Check and repair harness and connectors
between switch and motor. Replace power seat switch.
Replace reclining motor.
BE±344±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)
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OKNG
OKNG
INSPECTION PROCEDURE
1Check voltage between terminals B1 and E1 of power seat switch.
C
OK
PRemove power seat switch with connector still con-
nected.
Measure voltage between terminals B1 and E1 of power
seat switch connector.
Voltage: 10 ± 14 V
Check and repair harness and connectors between bat-
tery and power seat switch, power seat switch and body
ground.
2Check power seat switch.
C
OK
PDisconnect power seat switch connector.
Check continuity of each terminal shown below.
Switch Position
Terminal
Reclining
Neutral
Forward
Back
1625
Continuity
Replace power seat switch.
Go to step [3].
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)BE±345
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OKNG
3Check reclining motor.
C
OK
P
OK
C
(1) Remove seat.
(2) Disconnect reclining motor connector.
Connect battery
to terminal 1, and battery  to termi-
nal 2 of the reclining motor connector.
The seat back reclines.
Connect battery  to terminal 1, and battery
to termi-
nal 2 of the reclining motor connector.
The seat back returns to upright.
Replace reclining motor.
Check and repair harness connectors between
switch and motor.
BE±346±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)
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DOOR LOCK CONTROL SYSTEM
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±361
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DESCRIPTION
The door lock control system has a key±interlocked door lock and unlock \
function and a key±confinement pre-
vention function. All doors can be locked and unlocked simultaneously by\
key operation at the front right or left
door (the key needs to be operated twice to unlock the doors at the driver's door). If the door lock operation is
performed when one of the doors is open and the ignition key inserted in\
the key cylinder, doors are unlocked
automatically to prevent the ignition key from being left inside the veh\
icle. The luggage compartment door can
be opened by electromagnetic opener.
For the function of component parts of this system, refer to the circuit\
description in circuit inspection.
PARTS LOCATION
BE±362±
BODY ELECTRICAL SYSTEM Door Lock Control System
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DESCRIPTION
The door lock control system has a key±interlocked door lock and unlock f\
unction and a key±confinement pre-
vention function. All doors can be locked and unlocked simultaneously by\
key operation at the front right or left
door (the key needs to be operated twice to unlock the doors at the driver's door). If the door lock operation is
performed when one of the doors is open and the ignition key inserted in\
the key cylinder, doors are unlocked
automatically to prevent the ignition key from being left inside the veh\
icle. The luggage compartment door can
be opened by electromagnetic opener.
For the function of component parts of this system, refer to the circuit\
description in circuit inspection.
PARTS LOCATION
BE±362±
BODY ELECTRICAL SYSTEM Door Lock Control System
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±MEMO±
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±363
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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, ask the c\
ustomer in 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
ºProblem Simulation Methodº.
For example, if the malfunction involves failure of the lock or unlock duri\
ng operation of the Door Lock Con-
trol Switch, check if lock and unlock operation of the door using the key is\
normal or abnormal, and also
check if key confinement prevention function and luggage compartment door ope\
ner function are normal
or not. And having fully checked the extent of the malfunction.
 MATRIX CHART OF PROBLEM SYMPTOMS
Confirm the order of inspection for each applicable problem symptom on t\
he matrix chart.
 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, wire harness and connectors, or the ECU.
 REPAIR
When the cause of the problem is found in , perform repairs.
 CONFIRMATION TEST
After completing repairs, confirm that the problem is eliminated and that all functions of the door lock control
system are normal.
BE±364
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BODY ELECTRICAL SYSTEM Door Lock Control System
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Vehicle Brought to WorkshopProblem does
not occur
Problem
occurs Customer Problem Analysis
Problem Symptom Confirmation
Matrix Chart of Problem Symptoms P. BE±371 Symptom Simulation
P. IN±20
Chart Inspection
P. BE±376 ~ P. BE±392
Identification of Problem
RepairConfirmation Test
End Item inside are titles of pages in this manu-
al, with the page number indicated in the bottom
portion. See the indicated pages for detailed
explanations.
P. BE±366
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BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±365
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