LEXUS SC400 1991 Service Repair Manual

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
WhereEverybodyKnowsYourName

NGOK
OKNG
OKNG
*1: malfunction of the ECU can be considered possibleonly when the problem symptom is the following:

Lock and/or unlock using the Door Lock Con-
trol Switch cannot be done, neither on the driv-
er's side nor on the passenger's side.
INSPECTION PROCEDURE
1Check voltage between terminals 2(3), 1(1) of door lock control switch co\
nnector and body
ground.
C
OK
Hint
PRemove the door trim and service hole cover.
1. Turn ignition switch ON.
2. Measure voltage between terminals 2(3), 1(1) of door lock control switch connector and body
ground, when door lock control switch is pressed to
the lock side, unlock side and not pressed.
The terminal number without brackets is for the LH, the
number with brackets is for the RH.
Proceed to next circuit inspection shown on matrix chart
(See page BE±371).
2Check door lock control switch.
C
OK
Hint
PDisconnect the door lock control switch connector.
Check continuity between terminals 2(3), 1(1), and 8(2)
of door lock control switch connector, when door lock
control switch is pressed to the lock side, and unlock
side and not pressed.
The terminal number without brackets is for the LH, the
number with brackets is for the RH.
Replace door lock control switch.
3Check harness and connectors between ECU and door lock control switch, s\
witch and body
ground (See page IN±27).
Repair or replace harness or connector.
Check and replace ECU. *1
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±385
WhereEverybodyKnowsYourName

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
WhereEverybodyKnowsYourName

OKNG
OKNG
INSPECTION PROCEDURE
1Check door key lock and unlock switch.
C
OK
P1. Remove the door trim and service hole cover.
2. Disconnect the door ley lock and unlock switch con-
nector.
Check continuity between terminals 1, 2 and 3 of door
key lock and unlock switch is turned to the lock side, un-
lock side and not turned.
Replace door key lock and unlock switch.
2Check harness and connectors between ECU ans switch, switch and body ground (See page
IN±27 ).
Repair or replace harness or connector.
Proceed to next circuit inspection shown on ma-
trix chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±387
WhereEverybodyKnowsYourName

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
WhereEverybodyKnowsYourName

OKNG
OKNG
INSPECTION PROCEDURE
1Check key unlock warning switch.
C
OK
PDisconnect key unlock warning switch connector.
Check continuity between terminal 9 and 10 of key un-
lock warning switch connector, when the key is inserted
to the key cylinder or removed.
Replace key unlock warning switch.
2Check harness and connectors between ECU and key unlock warning switch, key un\
lock warn-
ing switch and body ground (See page IN±27).
Repair or replace harness or connector.
Proceed to next circuit inspection shown on ma-
trix chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±389
WhereEverybodyKnowsYourName

NG
OK
1
2
Proceed to next circuit inspection shown on
matrix chart (See page BE±371)
Check luggage compartment door opener
main switch and opener switch.
Check harness and connectors between ECU
and main switch, opener switch and body
ground (See page IN±27). Repair or replace harness or
connector.
NG
OK Replace luggage compartment door
opener main switch and/or opener
switch.
WIRING DIAGRAM
Luggage Compartment Door Opener Main Switch and
Opener Switch Circuit
CIRCUIT DESCRIPTION
The luggage compartment door opener main switch is off when it
is pushed in, and the luggage compartment door opener switch is
on when it is pulled.
The ECU energizes the luggage compartment door opener motor
only when the main switch and opener switch are on together.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
BE±390±
BODY ELECTRICAL SYSTEM Door Lock Control System
WhereEverybodyKnowsYourName

OKNG
OKNG
INSPECTION PROCEDURE
1Check luggage compartment door opener main switch and opener switch.
C
OK
P
OK
C
Disconnect the luggage compartment door opener
main switch and opener switch connector.
Check luggage compartment door opener main switch.
Check continuity between terminals of main switch con-
nector.
Check luggage compartment door opener switch.
Check continuity between terminals of main switch and
opener switch connector.
Replace luggage compartment door opener main switch
and or opener switch.
2Check harness and connector between ECU and main switch, opener switch and bo\
dy ground
(See page IN±27).
Repair or replace harness or connector.
Proceed t next circuit inspection shown on matrix
chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±391
WhereEverybodyKnowsYourName

1
2
NG
OK
Proceed to next circuit inspection shown on
matrix chart (See page BE±371)
Check door open detection switch.
Check harness and connectors between ECU and
door open detection switch, door open detection
switch and body ground (See page
IN±27).
Repair or replace harness or
connector.
NG
OK Replace door open detection
switch.
WIRING DIAGRAM
Door Open Detection Switch Circuit
CIRCUIT DESCRIPTION
The door open detection switch is built in the door lock assembly. It is on when the door is open and
off when the door is closed.
DIAGNOSTIC CHART
BE±392±
BODY ELECTRICAL SYSTEM Door Lock Control System
WhereEverybodyKnowsYourName

OKNG
OKNG
INSPECTION PROCEDURE
1Check door open detection switch
C
OK
P1. Remove the door trim and service hole cover.
2. Disconnect door open detection switch connector.
Check continuity between terminals 3 and 6 of door
open detection switch connector, when the front door is
opened and closed.
Replace door open detection switch.
2Check harness and connectors between ECU and door open detection switch,\
door open
detection switch and body ground (See page IN±27).
Repair or replace harness or connector.
Proceed to next circuit inspection shown on
matric chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±393
WhereEverybodyKnowsYourName