1991 LEXUS SC400 wiring

WIRING DIAGRAM
NGOK
*1 The power source is supplied to the actuator(Slide motor) through the passenger's seat
ECU accordingly, if a short circuit of the W/H
or actuator occurs in the actuator circuit, the
DOOR fusible link may become OPEN, so
also inspect the actuator.
(Slide motor circuit on page BE±328).
OKNG
INSPECTION PROCEDURE
1Check voltage between terminals SLDF, SLDR, of ECU connector and body ground.
C
OK
PRemove ECU with connector still connected.
Measure voltage between SLDF, SLDR terminal and
body ground, when slide switch is operated.
Switch condition Voltage (V)
SLDF SLDR
Forward
Back 10 ± 14 V Below 1 V
Below 1 V 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±319).
2Check DOOR fuse.
Check for short in all the harness and components con-
nected to the DOOR fuse and repair them (See attached
wiring diagram). *1
Go to step [3].
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)BE±335
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WIRING DIAGRAM
Buckle Switch Circuit
CIRCUIT DESCRIPTION
Buckle switch signal is sent to ECU when the passenger's seat belt is fastened.
When the signal is input to ECU, ECU prohibits operation of the power wa\
lk±in.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check buckle switch.
Check voltage between terminals PBCL
and SGND of ECU connector.
OK
NG
OK
OK NG
NG Proceed to next circuit inspection
shown on matrix chart (See page
BE±319
).
Replace the buckle switch.
Check the harness and connector between
buckle switch and ECU, ECU and battery. Repair or replace harness or
connector.
Check and replace ECU.
BE±338±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)
WhereEverybodyKnowsYourName

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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WIRING DIAGRAM
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±367
WhereEverybodyKnowsYourName

STANDARD VALUE OF ECU TERMINAL
 

Terminals 

Symbols 


Wiring
Color 

Condition 

Standard Value
 T9±3
e T9±4 ACT e ACT+ L±W e L±R Ignition switch OFF 50
or less
 T9±5 e T9±16 T0 e E B e W±B Ignition switch OFF 100
or less
 
T9 6 eT9 16
 
KSW eE
 
Ye WB
 Key unlock warning switch ON.
(Key is inserted into key cylinder). 1
or less
 


T9±6
e T9±16 


KSW
e E 


Y
e W±B 

Key unlock warning switch OFF.
(Key is not inserted into key cylinder). 

1 M

or higher
 

T9±7
e T9±16
 

LSWP
e E
 

P±B
e W±B
 


Door unlock detection switch ON.
(Passenger's) 

1

or less
    Door unlock detection switch OFF. 1 M
higher
 T9±8 e T9±16 +B2 e E L±W e W±B Always 10±14 V
 
T9 10 eT9 16
 
UL3 eE
 
Ge WB
 Door key lock and unlock switch ºunlockº
position. 1
or less
 


T9±10
e T9±16 


UL3
e E 


G
e W±B 

Door key lock and unlock switch OFF or
ºlockº position. 

1 M

or higher
 
T9 11 eT9 16
 
LSWD eE
 
WL eWB
 Door unlock detection switch ON. (driver's) 1
or less
 T9±11 e T9±16 LSWD e E W±L e W±B Door unlock detection switch OFF. (driver's) 1 M
or higher
 

T9 12
eT9 16
 

DSWP
eE
 

RW
eWB
 


Door open detection switch (passenger's)
ON (door opened). 

1

or less
 


T9±12
e T9±16 


DSWP
e E 


R±W
e W±B 


Door open detection switch (passenger's)
OFF (door closed). 


1 M

or higher
 
T9 13 eT9 16
 
DSWD eE
 
RB eWB
 Door open detection switch (driver's)
ON (door opened). 1
or less
 


T9±13
e T9±16 


DSWD
e E 


R±B
e W±B 

Door open detection switch (driver's)
OFF (Door closed). 

1 M

or higher
 

T9 14
eT9 16
 

L1
eE
 

GY
eWB
 


Door key lock and unlock switch ºlockº
position. 

1

or less
 


T9±14
e T9±16 


L1
e E 


G±Y
e W±B 


Door key lock and unlock switch OFF or
ºunlockº position. 


1 M

or higher
 
T9 15 eT9 16
 
UL1 eE
 
GW eWB
 Door key lock and unlock switch ºunlockº
position. 1
or less
 


T9±15
e T9±16 


UL1
e E 


G±W
e W±B 

Door key lock and unlock switch OFF or
ºlockº position. 

1 M

or higher
 


T9±16
e Body
Ground 


E
e Body
Ground 


W±B
e Body
Ground 

Always 

1

or less
    Door lock control switch ªlockº position. 1
or less
 

T9±17 e T9±16 

L2 e E 

R±B e W±B 

Door lock control switch OFF or ªunlockº
position. 

1 M
or higher
    Door lock control switch ªunlockº position 1
or less 

T9±18
e T9±16 

UL2
e E 

G±L
e W±B 

Door lock control switch OFF or ªlockº
position. 

1 M

or higher
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±369
WhereEverybodyKnowsYourName

 
Terminals Symbols WiringColor Condition Standard Value
 T9±19 e T9±16 TSW e E L e W±B Luggage compartment door opener switch ON. 1
or less 


 


 


 

Luggage compartment door opener switch
OFF. 

1 M

or higher
 T9±20 e T9±16 +B1 e E R e W±B Always 10±14 V
O When checking the voltage or resistance of theft deterrent and door lock\
ECU terminal, disconnect
the ECU connector.
BE±370
±
BODY ELECTRICAL SYSTEM Door Lock Control System
WhereEverybodyKnowsYourName

Check DOME fuse.NG OKCheck for short in all the harness
and components connected to the
DOME fuse (See attached wiring
diagram).1
Check and repair harness and connector
between ECU and battery. Proceed to next circuit inspection
shown on matrix chart (See page
BE±371
).
Repair or replace harness or
connector.
Check voltage between terminals +B1
and E of ECU connector.
Check for open in harness and connector
between ECU and body ground (See page
IN±27 ).
OK
OK
NG
NG
2
3
WIRING DIAGRAM
CIRCUIT INSPECTION
ECU Power Source Circuit
CIRCUIT DESCRIPTION
This circuit provides power to operate the theft deterrent and door lock ECU\
.
DIAGNOSTIC CHART
BE±376±
BODY ELECTRICAL SYSTEM Door Lock Control System
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