1991 LEXUS SC400 relay

103
CORNERING LIGHT RELAY 3±5 : CLOSED WITH LIGHT CONTROL SW AT HEAD POSITION
C15 LIGHT CONTROL SW [COMB. SW]
13±4 : CLOSED WITH LIGHT CONTROL SW AT HEAD POSITION
C16 CORNERING LIGHT SW [COMB. SW]
8±11 : CLOSED WITH TURN SIGNAL LEVER AT LEFT POSITION
8±10 : CLOSED WITH TURN SIGNAL LEVER AT RIGHT POSITION
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C 626C1528I16A29 (USA)
C 726C1628I16B29 (CANADA)
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
423LEFT KICK PANEL (J/B NO.1 LEFT)
523LEFT KICK PANEL (J/B NO.1 RIGHT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1I
1J20COWL WIRE
1K
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EA34FRONT SIDE OF RIGHT FENDER
IF36LEFT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
E 434ENGINE ROOM MAIN WIRE
12 56
X1213 A
B
C 6, C 7 C15 C16 I16
I1 6
(
CA NA DA ) (
US A )
BLACK
GRAY
X
XXX13 4
X
X X
8X 10 11
SERVICE HINTS
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152
CRUISE CONTROL
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C 326C1928P 329
C 826C2328S1229
C12B28C2428T 629
C14A28E 9A28
C1528E10B28
: 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
1E20INSTRUMENT PANEL WIRE
1H
1I20COWL WIRE
1K
20COWL WIRE
3A
3C
3D22INSTRUMENT PANEL WIRE3E22INSTRUMENT PANEL WIRE
3F
3H
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IE236ENGINE ROOM MAIN WIRE AND COWL WIRE (BEHIND GLOVE BOX)
IG136INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)
IJ136ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)IJ236ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)
IK136ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EA34FRONT SIDE OF RIGHT FENDER
IG36INSTRUMENT PANEL BRACE LH
IH36UNDER THE ASHTRAY LH
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I 738COWL WIREI 938COWL WIRE
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126
ECT AND A/T INDICATOR
21I
5
22 EB1 8 EB14
A
24 A 33 A 12 A1
A
32 A 31 B 10 B8
22
EB2
3
I33 IJ2
11
EB B±Y
B±O
B±R
B±Y
B±O B±Y
B±O
W±B
B±R
B±Y
BR±Y B±O B±O
B±R
B±R
LG
R±L
B±R
W±B
FROM POWER SOURCE SYSTEM (
SEE PAGE 56 )
30A
EFI
3
13
WY
M±REL BATT OD1 IGSW +B1 +B S1 S3
FROM
CRUISE CONTROL ECU (
OD )
7. 5A
IGN
21
43
ENGINE AND ECT ECU
ECT SOLENOID
E9
,E10
B
A
NO. 1
NO. 3
EFI
MAIN
RELAY 4
B
9
W±R
2
B
S2
NO. 2
E1
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132
ECT AND A/T INDICATOR
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A2128E 226S 927
C 326E 828S22B29
C12C28E 9A28S23A29
C13B28E10B28T 227
C14A28N 127T 629
D1326O 529S 327
E 126S 427
: 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)
1E20INSTRUMENT PANEL WIRE
1H
1I20COWL WIRE1J20COWL WIRE
1K
3A
3B22INSTRUMENT PANEL WIRE3D22INSTRUMENT PANEL WIRE
3H
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
EB134ENGINE WIRE AND ENGINE ROOM MAIN WIRE (FRONT SIDE OF R/B NO 2)EB234ENGINE WIRE AND ENGINE ROOM MAIN WIRE (FRONT SIDE OF R/B NO. 2)
IG236INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)
IJ136ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)IJ236ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)
IK136ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EB34FRONT SIDE OF LEFT FENDER
ED34REAR SIDE OF CYLINDER HEAD RH
IF36LEFT KICK PANEL
IH36UNDER THE ASHTRAY LH
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
E1834ENGINE WIREI2238INSTRUMENT PANEL WIRE
E2034ENGINE WIREI3238ENGINE WIREI1938INSTRUMENT PANEL WIREI3338ENGINE WIRE
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66
.
ENGINE CONTROL
THIS SYSTEM UTILIZES AN ECU AND MAINTAINS OVERALL CONTROL OF THE ENGINE, TRANSMISSION AND SO ON. AN OUTLINE O\
F
THE ENGINE CONTROL IS EXPLAINED HERE.
1. INPUT SIGNALS
(1) WATER TEMP. SIGNAL CIRCUITTHE WATER TEMP. SENSOR DETECTS THE ENGINE COOLANT TEMP. AND HAS A BUILT±IN THERMISTOR WITH A RESISTANCE
WHICH VARIES ACCORDING TO THE WATER TEMP. THE WATER TEMP. IS INPUT INTO TERMINAL THW OF ENGINE CONTROL
ECU AS A CONTROL SIGNAL.
(2) INTAKE AIR TEMP. SIGNAL CIRCUIT THE INTAKE AIR TEMP. SENSOR IS INSTALLED IN THE AIR FLOW METER AND DETECTS THE INTAKE AIR TEMP., WHICH IS INPUT
AS A CONTROL SIGNAL TO TERMINAL THA OF ENGINE CONTROL ECU.
(3) OXYGEN SENSOR SIGNAL CIRCUIT THE OXYGEN DENSITY IN THE EXHAUST EMISSION IS DETECTED AND INPUT AS A CONTR\
OL SIGNAL FROM THE OXYGEN
SENSOR NO. 1 AND NO. 2 TO TERMINALS OX1, OX2 OF THE ECU AND FROM THE OXYGEN SENSOR SUB (FOR CALIFORNIA) TO
TERMINAL OX3 OF THE ECU.
TO STABILIZE DETECTION PERFORMANCE BY THE OXYGEN SENSOR SUB (FOR CALIFORNIA)\
IS WARMED. THIS HEATER IS
ALSO CONTROLLED BY THE ECU (HT).
(4) RPM SIGNAL CIRCUIT CRANKSHAFT POSITION IS DETECTED BY THE PICK±UP COIL INSTALLED INSIDE THE DISTRIBUTOR. CRANKSHAFT POSITION
IS INPUT AS A CONTROL SIGNAL TO TERMINALS G1 AND G2 OF THE ECU, AND RPM IS INPUT TO TERMINAL NE.
(5) THROTTLE SIGNAL CIRCUIT THE THROTTLE POSITION SENSOR DETECTS THE THROTTLE VALVE OPENING ANGLE AS A CONTROL SIGNAL, WHICH IS
INPUT INTO TERMINAL VTA1 OF THE ECU. WHEN THE VALVE IS COMPLETELY CLOSED, THE CONTROL SIGNAL IS INPUT INTO
TERMINAL IDL1 .
(6) VEHICLE SPEED CIRCUIT THE VEHICLE SPEED IS DETECTED BY SPEED SENSOR NO. 1 INSTALLED IN THE TRANSMISSION AND THE SIGNAL IS INPUT TO
TERMINAL SPD OF THE ECU VIA THE COMB. METER.
(7) NEUTRAL START SIGNAL CIRCUIT THE NEUTRAL START SW DETECTS WHETHER THE SHIFT POSITION IS IN NEUTRAL OR NOT, AND THE SIGNAL IS INPUT INTO
TERMINAL NSW OF THE ECU.
(8) AIRCONDITIONING SW SIGNAL CIRCUIT THE OPERATING VOLTAGE OF THE A/C MAGNETIC CLUTCH IS DETECTED AND THE SIGNAL IS INPUT INTO TERMINAL ACMG OF
ECU AS A CONTROL SIGNAL.
(9) BATTERY SIGNAL CIRCUIT VOLTAGE IS CONSTANTLY APPLIED TO TERMINAL BATT OF THE ECU. WITH THE IGNITION SW TURNED ON, THE VOLTAGE FOR
ECU START±UP POWER SUPPLY IS APPLIED TO TERMINALS +B AND +B1 OF ECU VIA EFI MAIN RELAY.
THE CURRENT FLOWING THROUGH THE IGN FUSE FLOWS TO TERMINAL IGSW OF THE ECU.
(10) INTAKE AIR VOLUME SIGNAL CIRCUIT INTAKE AIR VOLUME IS DETECTED BY THE AIR FLOW METER AND THE SIGNAL IS INPUT TO TERMINAL KS OF THE ECU AS A
CONTROL SIGNAL.
(11) STOP LIGHT SW SIGNAL CIRCUIT THE STOP LIGHT SW IS USED TO DETECT WHETHER OR NOT THE VEHICLE IS BRAKING AND THE SIGNAL IS INPUT INTO
TERMINAL STP OF THE ECU AS A CONTROL SIGNAL.
(12) STA SIGNAL CIRCUIT TO CONFIRM WHETHER THE ENGINE IS CRANKING, THE VOLTAGE APPLIED TO THE STARTER MOTOR DURING CRANKING IS
DETECTED AND THE SIGNAL IS INPUT INTO TERMINAL STA OF THE ECU AS A CONTROL SIGNAL.
(13) ENGINE KNOCK SIGNAL CIRCUIT ENGINE KNOCKING IS DETECTED BY KNOCK SENSOR NO. 1 AND NO. 2 AND THE SIGN\
AL IS INPUT INTO TERMINALS KNK1 AND
KNK2 AS A CONTROL SIGNAL.
SYSTEM OUTLINE
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69
E2022 22
1H
12
2
22
22 1I
10
P
N
3
2
1 2
EB2
1
IE1
15 IJ2
7 IJ1
10 IK1 7
IK1
6
1J
3
1E12
31 23 132
1
4
52 I32
EB1
3 EB2 1
VCC OUT GNDY
L±R
B±O B
Y
B
L±R
W
B±O
B±R B±Y
B±W
B±R B±O
B±W B±O
Y
B
L±R
W
B±O
B±R B±R
B±W
B±O
B
B
B
B±R B±R B±Y
W±B
W Y
R
L±R Y
G±W
G±W B±O B
L±O
B
B
B±WB±Y
R
L±O
NEUTRAL
START SW
FROM POWER SOURCESYSTEM(
SEE PAGE 56 )
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
STARTER
RELAY S3
S12N1
7. 5A
IGN
30A
EFI
15A
STOP10A
GAUGE
SPEED SENSOR NO. 1
EFI MAIN
RELAY
STOP LIGHT
SW
TO THEFT DETERRENT
ANDDOORLOCK
ECU (
ST )
TO STARTER
4
3
B±Y
B±Y EB1
8
G±W
W
2 1 IJ 2
8
1I
5
C23
CLUTCH
START
SW B
B
( A/T )
(
M/T )
(
A/T )
B±W
( M/T ) IJ1
6
(A/T )
EB
W±B
B±W
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73
* 1 : W/ CD PLAYER
* 3 : FOR USA SPEC. *2:W/OCDPLAYER
8 13 715 2
3411912 8 3
E20 I32
I32
IJ 1 1 IK1
3
IK1
4
IK1
5IK1 2
EB1
2II1 5
B
4 E11
B
69 E1
B
28 VF2
B
29 VF1
A
20 TE1
A
3 KD
A
17 TT
A
23
ACMG A
34
A/C
IF
ED
BR
WGB
L±Y
B±R BR
B±R B±R
B±RLG
GR±Y
W
L±O
L±R W
GR±Y LG
GR±Y LG
B±Y BR
GR±Y LG
G±R
G±Y G±R
L
BR
L±Y B±R
B
G
W
BR
W
E1
+B
IG±
FP
OX
E1
OX2 TE1 VF1 ENG TE1 TT TE2 E11 , E1 2
T6
C3
FROM A/C MAGNETIC
CLUTCH RELAY
FROM A/C CONTROL
ASSEMBLY
ENGINE ECU (
M/T )
CHECK CONNE CTOR TDCL
(TOTAL DIAGNOSTIC
COMMUNICATION LINK )
A
B
IJ 1 12
R±L
I33
I32
BR
15 VF2
14
BR
BR
EC
E9 ,E10
ENGINE AND ECT ECU
(
A/T )
AB
IH1
2 IJ2
17
1 2IH1
1
A
19 TE 2
G±Y
W±B W±B L L
( SHIELDED )
(
SHIELDED )
B±R
BR B±R
(
SHIELDED )
KICK DOWN
SW
K3
BR
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74
ENGINE CONTROL
EFI MAIN RELAY2 ± 4: CLOSED WITH IGNITION SW AT ON OR ST POSITION
W 4 WATER TEMP. SENSOR
1 ± 2: APPROX. 16.2K (±20 °C, ±4°F)
: APPROX. 2.45K (20 °C, 68°F)
: APPROX. 0.32K (80 °C, 176 °F)
E 3 EGR GAS TEMP. SENSOR (FOR USA SPEC.)
1 ± 2: APPROX. 78.30K (50 °C, 122 °F)
APPROX. 13.06K (100 °C, 212 °F)
APPROX. 3.16K (150 °C, 302 °F)
E 9(A), E10(B) ENGINE AND ECT ECU, E11(A), E12(B) ENGINE ECU
(VOLTAGE AT ENGINE AND ECT ECU WIRING CONNECTORS)
BATT ± E1 : ALWAYS APPROX. 12 VOLTS
IGSW ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
+B, +B1 ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
VC ± E2 : 4±6 VOLTS WITH IGNITION SW ON
IDL1, IDL2 ± E2 : 0±1 VOLTS WITH IGNITION SW ON AND THROTTLE VALVE FULLY CLOSED
: 10±14 VOLTS WITH IGNITION SW ON AND THROTTLE VALVE FULLY OPEN
VTA1, VTA2 ± E2 : 0.1±1.0 VOLTS WITH IGNITION SW ON AND THROTTLE VALVE FULLY CLOSED
: 3±6 VOLTS WITH IGNITION SW ON AND THROTTLE VALVE FULLY OPEN
THA ± E2 : 1±3 VOLTS WITH IGNITION SW ON AND INTAKE AIR TEMP. 20°C ( 68°F)
THW ± E2 : 0.1±1.0 VOLTS WITH IGNITION SW ON AND COOLANT TEMP. 80°C ( 176 °F)
STA ± E1 : 6±14 VOLTS WITH ENGINE CRANKING
#10, #20, #30, #40, #50, #60 ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
IGF ± E1 : 0±1 VOLTS WITH ENGINE IDLING
MREL ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
DI ± E1 : 7.5±14 VOLTS WITH ENGINE IDLING
ISC1, ISC2, ISC3, ISC4 ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
HTL1, HTR1, HTL2, HTR2 ± E01 : 0±2 VOLTS WITH ENGINE IDLING
EGR ± E1 : APPROX. 12 VOLTS WITH ENGINE IDLING
NSW ± E1 : 0±1 VOLTS WITH IGNITION SW ON AND SHIFT LEVER P OR N RANGE
: 10±14 VOLTS WITH IGNITION SW ON AND SHIFT EXCEPT P OR N RANGE
TE1 ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
TE2 ± E2 : APPROX. 12 VOLTS WITH IGNITION SW ON
W ± E1 : APPROX. 12 VOLTS WITH ENGINE IDLING
0±2 VOLTS WITH IGNITION SW ON
A/C ± E1 : 0±2 VOLTS WITH AIR CONDITIONER ON
10±14 VOLTS WITH AIR CONDITIONER OFF
ACMG ± E1 : 0±2 VOLTS WITH AIR CONDITIONER ON
: 10±14 VOLTS WITH AIR CONDITIONER OFF
TR ± E1 : APPROX. 12 VOLTS WITH IGNITION SW ON
VTA1, VTA2 ± E2 : 0±1 VOLTS WITH IGNITION SW ON AND THROTTLE VALVE FULLY CLOSED
3±5.5 VOLTS WITH IGNITION SW ON AND THROTTLE VALVE FULLY OPEN
NE ± E1 : 4±6 VOLTS WITH IGNITION SW ON
(RESISTANCE OF ENGINE AND ECT ECU WIRING CONNECTORS)
+B, +B1 ± #10, #20, #30, #40, #50, #60 : 13.2±14.2
+B, +B1, ISC1, ISC2, ISC3, ISC4 : 10±30
+B, +B1 ±EGR: 33±39
+B, +B1, HT : 5.1±6.3
+B, +B1 ±EVAP : 30±34
IDL1, IDL2 E2 : INFINITY WITH THROTTLE VALVE OPEN 0±0.5WITH THROTTLE VALVE FULLY CLOSED
VTA1, VTA2 E2 : 2.4±10.7WITH THROTTLE VALVE FULLY OPEN
0.3±5.9 WITH THROTTLE VALVE FULLY CLOSED
VCC ± E2 : 3±7K
THW ± E2 : 200±400 WITH COOLANT TEMP. 80°C ( 176 °F)
THA ± E2 : 2±3K WITH INTAKE AIR TEMP. 20°C ( 68°F)
THG ± E2 : 69.4±88.5K WITH EGR GAS TEMP. 50°C ( 11 2 °F)
G1, G2 ±G± : 0.835±13.5K
NE± G± : 0.835±13.5K
SERVICE HINTS
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