1991 LEXUS SC400 wiring

OKNG
NGOK
OKNG
INSPECTION PROCEDURE
1Check DOME fuse.
C
OK
PRemove DOME fuse from R/B No. 2.
Check continuity of DOME fuse.
Continuity
Check for short in all the harness and components con-
nected to the DOME fuse (See attached wiring diagram).
2Check voltage between terminals +B1 and E of ECU connector.
C
OK
P1. Remove the No. 1 under cover and heater duct.
2. Disconnect the theft deterrent and door lock ECUconnectors.
Measure voltage between terminals +B1 and E of ECU
connector.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±371).
3Check for open in harness and connector between ECU and body ground (Se\
e page IN±27).
Repair or replace harness or connector.
Check and repair harness and connector between
ECU and battery.
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±377
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NGOK
NG
OK
1
2
Check P/W fuse.
Check voltage between terminal +B2 of
ECU connector and body ground.
Check and repair harness and connectors
between ECU and battery
(See page IN±27). Check for short in all the harness
and components connected to the
DOOR fuse (See attached wiring
diagram).
*1
Proceed to next circuit inspection
shown on matrix chart (See page
BE±371
).
WIRING DIAGRAM
*1: The power source is supplied to the actuator
(door lock motor, luggage compartment door
opener motor) through the theft deterrent and
door lock ECU. Accordingly, if a short circuit of
the W/H or actuator occurs in the actuator circuit,
the DOOR fuse may become OPEN. so also in-
spect the actuator (door lock motor circuit on
page BE±380 , and the luggage compartment
door opener motor circuit on page BE±382).
Actuator Power Source Circuit
CIRCUIT DESCRIPTION
This circuit provides power to drive the door lock motor and the luggage com\
partment door opener mo-
tor.
DIAGNOSTIC CHART
BE±378±
BODY ELECTRICAL SYSTEM Door Lock Control System
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OKNG
NGOK
*1: The power source is supplied to the actuator (doorlock motor, luggage compartment door opener mo-
tor) through the theft deterrent and door lock 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
(door lock motor circuit on page BE±380, and the
luggage compartment door opener motor circuit on
page BE±382 ).
INSPECTION PROCEDURE
1Check DOOR fuse.
C
OK
P1. Remove the No. 1 under cover and LH lower pad.
2. Remove the DOOR fusible link from J/B No. 1.
Check continuity of DOOR fuse.
Continuity
Check for short in all the harness and components con-
nected to the DPPR fusible link (See attached wiring dia-
gram). *1
2Check voltage between terminal +B2 of ECU connector and body ground.
C
OK
P1. Remove No. 1 under cover and heater duct.
2. Disconnect the theft deterrent and door lock ECU connector.
Measure voltage between terminal +B2 of ECU connec-
tor and body ground.
Voltage: 10 ± 14 V
Proceed to next circuit inpsection shown on matrix chart
(See page BE±371).
Check and repair harness and connectors be-
tween ECU and battery (See page IN±27).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±379
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NG
Check operating sound of door lock
motor.
OK NG OK
Check door lock motor.
Check and harness connectors between ECU
and door lock motor (See page IN±27). Replace door lock motor.
1
2
WIRING DIAGRAM
Proceed to next circuit inspection
shown on matrix chart (See page
BE±371
). Repair or replace door lock control
link.
Repair or replace harness or
connector.
3
OK
NG
Door Lock Motor Circuit
CIRCUIT DESCRIPTION
The door lock motor locks and unlocks the door in accordance with signals f\
rom the ECU.
DIAGNOSTIC CHART
HINT: Inspect the door which is malfunctioning.
BE±380
±
BODY ELECTRICAL SYSTEM Door Lock Control System
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NG
Check voltage between terminal 1 of lug-
gage compartment door opener motor and
body ground.
OK NG
OK
Check luggage compartment door opener
motor.
Proceed to next circuit inspection
shown on matrix chart (See page
BE±371 ). Check harness and connectors
between ECU and luggage
compartment door opener motor
(See page
IN±27).
Replace luggage compartment
door motor.
1
2
WIRING DIAGRAM
Luggage Compartment Door Opener Motor Circuit
CIRCUIT DESCRIPTION
This circuit unlocks the luggage compartment door when the ECU sends signals\
to the luggage
compartment door opener motor.
DIAGNOSTIC CHART
BE±382±
BODY ELECTRICAL SYSTEM Door Lock Control System
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Door Lock Control Switch Circuit
CIRCUIT DESCRIPTION
When the door lock control switch is pushed to the lock side, Lock terminal of the swi\
tch is grounded,
and when the switch is pushed to the unlock side, Unlock terminal is grounded (See wiring diagram
below).
WIRING DIAGRAM
NG
Check voltage between terminals 2 (3), 1(1)
of door lock control switch connector and
body ground.
OK NG OK
Check door lock control switch.
Check harness and connectors between ECU
and door lock control switch, switch and body
ground (See page IN±27). Replace door lock control switch.
1
2
Proceed to next circuit inspection
shown on matrix chart (See page
BE±371
).
Check and replace ECU Repair or replace harness or
connector.
3
OK
NG
DIAGNOSTIC CHART
BE±384±
BODY ELECTRICAL SYSTEM Door Lock Control System
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Door Key Lock and Unlock Switch Circuit
CIRCUIT DESCRIPTION
The door key lock and unlock switch is built in the door key cylinder.
When the key is turned to the lock side, terminal 3 of the switch is grounde\
d and when the key is turned
to the unlock side, terminal 1 of the switch is grounded.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
OKOK NG NG
Check door key lock and unlock switch.
Check harness and connectors between ECU
and switch, switch and body ground
(See page IN±27). Replace door key lock and unlock
switch.
1
2
Proceed to next circuit inspection shown on
matrix chart (See page
BE±371). Repair or replace harness or
connector.
WIRING DIAGRAM
BE±386±
BODY ELECTRICAL SYSTEM Door Lock Control System
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OKOK NG NG
Check key unlock warning switch.
Check harness and connectors between ECU and
key unlock warning switch, key unlock warning
switch and body ground (See page
IN±27).
Replace key unlock warning
switch.1
2
Proceed to next circuit inspection shown on
matrix chart (See page BE±371). Repair or replace harness or
connector.
WIRING DIAGRAM
Key Unlock Warning Switch Circuit
CIRCUIT DESCRIPTION
The key unlock warning switch goes on when the ignition key is inserted in the key cylinder and goes
off when the ignition key is removed.
The ECU operates the key confinement prevention function while the key unlo\
ck warning switch is on.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
BE±388±
BODY ELECTRICAL SYSTEM Door Lock Control System
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