1991 LEXUS SC400 ignition system

11 5
CURRENT ALWAYS FLOWS TO TERMINAL (A)8 OF THE DOOR LOCK ECU THROUGH THE DOOR FUSE, AND TO TERMINAL (A)20
THROUGH THE DOME FUSE.
WHEN THE IGNITION SW IS TURNED ON, THE CURRENT FLOWING THROUGH THE ECU±IG FUSE " TERMINAL (A)2 OF THE ECU "
TERMINAL (B)8 FLOWS THROUGH THE COIL SIDE OF THE POWER MAIN RELAY TO GROUND, CAUSING THE RELAY TO OPERATE.
THE CURRENT FLOWING THROUGH THE POWER FUSE FLOWS TO THE DOOR LOCK CONTROL SW LH, CAUSING THE INDICATOR
LIGHT TO LIGHT UP.
1. MANUAL LOCK OPERATION
WHEN THE DOOR CONTROL SW OR KEY SW ARE PUSHED TO LOCK POSITION, A LOCK SIGNAL IS INPUT TO TERMINAL (A)17, (A)14
(FOR KEY SW) OF THE DOOR LOCK ECU AND CAUSES THE ECU TO FUNCTION. CURRENT FLOWS FROM TERMINAL (A)8 OF THE
ECU " TERMINAL (A)4 " TERMINAL 5 OF THE DOOR LOCK MOTORS " TERMINAL 2 " TERMINAL (A)3 OF THE ECU " TERMINAL
(A)16 " TO GROUND AND THE DOOR LOCK MOTOR CAUSES THE DOOR TO LOCK.
2. MANUAL UNLOCK OPERATION
WHEN THE DOOR LOCK CONTROL SW OR KEY ARE PUSHED TO UNLOCK POSITION, AN UNLOCK SIGNAL IS INPUT TO TERMINAL
(A)18, (A)10 (FOR KEY SW LH) OR (A)15 (FOR KEY SW RH) OF THE DOOR LOCK ECU AND CAUSES THE ECU TO FUNCTION.
CURRENT FLOWS FROM TERMINAL (A)8 OF THE ECU " TERMINAL (A)3 " TERMINAL 2 OF THE DOOR LOCK MOTORS " TERMINAL
5 " TERMINAL (A)4 OF THE ECU "TERMINAL (A)16 " TO GROUND AND THE DOOR LOCK MOTOR CAUSES THE DOOR TO
UNLOCK.
WHEN UNLOCK OPERATION OCCURS USING THE LH DOOR KEY SW, PERFORMING THE UNLOCK OPERATION ONCE UNLOCKS
ONLY THE DRIVER'S DOOR. TO UNLOCK ALL THE OTHER DOORS TOGETHER, UNLOCK OPERATION MUST BE PERFORMED AGAIN
WITHIN 3 SECONDS OF THE FIRST OPERATION.
3. IGNITION KEY REMINDER OPERATION
* OPERATION OF DOOR LOCK BUTTON (OPERATION OF DOOR LOCK MOTORS)
WHEN THE IGNITION KEY IS IN THE CYLINDER (UNLOCK WARNING SW ON) AND THE DOOR IS OPENED AND LOCKED USING
DOOR LOCK BUTTON (DOOR LOCK MOTOR), THE DOOR IS LOCKED ONCE BUT EACH DOOR IS UNLOCKED SOON BY THE
OPERATION OF THE ECU. AS A RESULT OF ECU ACTIVATION, THE CURRENT FLOWS FROM TERMINAL (A)8 OF THE ECU "
TERMINAL (A)3 " TERMINAL 2 OF THE DOOR LOCK MOTORS " TERMINAL 5 " TERMINAL (A)4 OF THE ECU " TERMINAL (A)16
" TO GROUND AND CAUSES ALL THE DOORS TO UNLOCK.
THE SAME APPLIES TO OPERATION OF THE DOOR LOCK CONTROL SW AND DOOR LOCK KEY SW.
* KEY LESS LOCK OPERATION
WHEN THE IGNITION KEY IS STILL INSERTED IN THE CYLINDER (UNLOCK WARNING SW ON), THE DOOR IS OPEN AND UNLOCK
OPERATION IS PREVENTED BY KEEPING THE DOOR LOCK BUTTON PRESSED TO THE LOCK SIDE, THE DOOR IS KEPT IN THE
LOCK CONDITION. IF THE DOOR IS THEN CLOSED, A SIGNAL IS INPUT TO THE ECU FROM THE DOOR COURTESY SW. THIS
ACTIVATES THE ECU AND EACH DOOR IS UNLOCKED.
SYSTEM OUTLINE
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184
UNLOCK AND SEAT BELT WARNING
1E
12
3A
4
3D
13
1B
5 2
B
1
A
7
1E 1
1H
13
1D
10
1J
1 1C
12 1D 8
1I
15
9
10
6 3
2
1
BK
IF 10A
DOME
10A
GAUGE
SEAT BELT
WARNING LIGHT
[COMB. METER]
INTEGATION RELAY
BUZZER TI M ER
UNLOCK
WARNING SW
[IGNITION SW] BUCKLE
SW LH
DOOR OPEN
DETECTION
SW LH
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
FROM POWER SOURCE SYSTEM(
SEE PAGE 56 )
C12 ,C 14
D10
B4
I15
R
R
Y
Y
W±B
W±B
W±B
Y
W±B
W±B
W±B W±B B±L B±L
R±W
W±B
W±B
V
86
5
10 179
AB
1 2
(W/ MEMORY )
( W/O MEMORY )
( W/ MEMORY )
( W/O MEMORY )
Ba1
14
Ba2
5 Ba2
6 Ba1
11
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185
CURRENT ALWAYS FLOWS TO TERMINAL 1 OF THE INTEGRATION RELAY THROUGH DOME FUSE.
1. SEAT BELT WARNING SYSTEM
WHEN THE IGNITION SW IS TURNED ON, CURRENT FLOWS FROM THE GAUGE FUSE TO TERMINAL 7 OF THE INTEGRATION RELAY.
AT THE SAME TIME, CURRENT FLOWS TO TERMINAL 9 OF THE RELAY FROM THE GAUGE FUSE THROUGH THE SEAT BELT
WARNING LIGHT. THIS CURRENT ACTIVATES THE INTEGRATION RELAY AND, FOR APPROX. 4±8 SECONDS, CURRENT FLOWING
THROUGH THE WARNING LIGHT FLOWS FROM TERMINAL 9 OF THE RELAY " TERMINAL 10 " GROUND, CAUSING THE WARNING
LIGHT TO LIGHT UP. AT THE SAME TIME AS THE WARNING LIGHT LIGHTS UP, A BUCKLE SW OFF SIGNAL IS INPUT TO TERMINAL 8
OF THE RELAY, THE CURRENT FLOWING TO TERMINAL 7 OF THE RELAY FLOWS FROM TERMINAL 10 " GROUND AND THE SEAT
BELT WARNING BUZZER SOUNDS FOR APPROX. 4±8 SECONDS. HOWEVER, IF THE SEAT BELT IS PUT ON DURING THIS PERIOD
(WHILE THE BUZZER IS SOUNDING), SIGNAL INPUT TO TERMINAL 8 OF RELAY STOPS AND THE CURRENT FLOW FROM TERMINAL 7
OF THE RELAY " TERMINAL 10 " GROUND IS CUT, CAUSING THE BUZZER TO STOP.
2. UNLOCK WARNING SYSTEM
WITH THE IGNITION KEY INSERTED IN THE KEY CYLINDER (UNLOCK SW ON), THE IGNITION SW STILL OFF AND \
DOOR OPEN (DOOR
COURTESY SW ON), WHEN A SIGNAL IS INPUT TO TERMINAL 6 OF THE RELAY, THE INTEGRATION RELAY OPERATES, CURRENT
FLOWS FROM TERMINAL 7 OF THE RELAY " TERMINAL 10 " GROUND AND UNLOCK WARNING BUZZER SOUNDS.
B 4 BUCKLE SW LH
1±2 : CLOSED WITH DRIVER'S LAP BELT IN USE
D10 DOOR COURTESY SW LH
3±6 : CLOSED WITH LH DOOR OPEN
I15 UNLOCK WARNING SW [IGNITION SW]
10±9: CLOSED WITH IGNITION KEY IN CYLINDER
INTEGRATION RELAY
10±GROUND: ALWAYS CONTINUITY6±GROUND: CONTINUITY WITH DRIVER'S DOOR OPEN
5±GROUND: CONTINUITY WITH IGNITION KEY IN CYLINDER
8±GROUND: CONTINUITY WITH DRIVER'S LAP BELT IN USA
9±GROUND: 0 VOLTS FOR 4±8 SECONDS WITH IGNITION SW ON AND APPROX. 12 VOLTS 4±8 SECONDS AFTER IGNITION SW ON
1±GROUND: ALWAYS APPROX. 12 VOLTS
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
B 432C14B28I1529
C12A28D1030
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1C20FLOOR MAIN
1D20FRONT DOOR LH WIRE
1E20INSTRUMENT PANEL WIRE
1H
1I20COWL WIRE
1J
20COWL WIRE
3A22INSTRUMENT PANEL WIRE3D22INSTRUMENT PANEL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
Ba142FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)Ba242FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
BK40UNDER THE CENTER PILLAR LH
SYSTEM OUTLINE
SERVICE HINTS
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