ect LEXUS SC300 1991 Service Repair Manual

15
ABBREVIATIONS
DISCONNECTION AND CONNECTION OF BOLT
TYPE CONNECTORS
For engine and ECT ECU in this vehicle, connectors are used
which require a bolt built into the connector to be screwed down to
securely connect the connector.
1. Disconnect the connectorAfter completely loosening the bolt, the two parts of the
connector can be separated.
NOTICE:
Do not pull the wire harness when disconnecting the
connector.
2. Connect the connector
NOTICE:
Before connecting the connector, always check that the
terminals are not bent or damaged.
(a) Match the guide section of the male connectorcorrectly with the female connector, then press them
together.
(b) Tighten the bolt. Make sure the connectors are completely connected,
by tightening the bolt until there is a clearance of less
than 1 mm (0.04 in.) between the bottom of male
connector and the end of female connector.
ABBREVIATIONS
The following abbreviations are used in this manual.
A/C = Air Conditioning O/D = Overdrive
ABS = Anti±Lock Brake System R/B = Relay Block
A/T = Automatic Transmission RH = Right±Hand
CB = Circuit Breaker SRS = Supplement Restraint System
COMB. = Combination SW = Switch
ECT = Electronic Controlled Transmission TDCL = Total Diagnostic Communication Link
ECU = Electronic Control Unit TEMP. = Temperature
EGR = Exhaust Gas Recirculation TRAC = Traction Control
FL = Fusible Link VSV = Vacuum Switching Valve
ISC = Idle Speed Control W/ = With
J/B = Junction Block W/O = Without
LH = Left-Hand
* The titles given inside the components are the names of the terminals (ter\
minal codes) and are not treatedas being abbreviations.
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144
ABS (ANTI±LOCK BRAKE SYSTEM)
M
A
11
MR A
4
R± A
5
SR
A
6 SFL
A
12 SRR
A
8 AST
A
9 MT
B
1 SFR
B
16 PKB
B
2 GND
B
13 GND
B
1B 4 B
3B 2B5
A 4
A 3
A 1 2 1
IG1
19
IO1
5IO1 7
EB EA 16 22 23 11
EB1
6IK1 10
IJ
EA 1
34
3 2
16
1
4
2
IK2
25 IK2 2
IE1
1
IE2
12
2 1
E10
I23I25
E9
2
6 6
666
66
66
6
B
10
WA
B
6
TS
5
6
E12 L
P±B
V±Y
L±W
L±W L
W
V±YL
W± B L±W V±YY±L
R
R
R
B±R
B±R
B±R
P±B
V
L
L
L V
L V±Y
V
R±Y
Y
B±Y P
L±W Y±G
R±W R±W
W±B
W±B
R±W
R±W
B
B
W±B
W±B W±B
W±B W±B
L±WL
W± B
SFR SFL SRR AST MT
BS
BM
GND WA
TS TC
WB
BATTERY ABS ECU
(
W/O TRACTION CONTROL )
R
120A ALT
60A ABS NO. 1
ABS MOTOR
RELAY
ABS ACTUATOR
RELAY
CHECK
CONNECTOR
FUSE BLOCK
R±W
DIODE
(FOR PARKING BRAKE )
BRAKE FLUID
LEVEL SW
PARKING
BRAKE
SW
ABS ACTUATOR
(
CANA DA )
( USA )
B1
D2
A4 , A33
P3
A2 2
,A23
B
BA A
C3
F9 SHORT PIN
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146
ABS (ANTI±LOCK BRAKE SYSTEM)
THIS SYSTEM CONTROLS THE RESPECTIVE BRAKE FLUID PRESSURES ACTING ON THE DISC\
BRAKE CYLINDERS OF THE RIGHT
FRONT WHEEL, LEFT FRONT WHEEL AND REAR WHEELS WHEN THE BRAKES ARE APPLIED IN \
A PANIC STOP SO THAT THE
WHEELS DO NOT LOCK. THIS RESULTS IN IMPROVED DIRECTIONAL STABILITY AND STEERABILITY DURING PANIC BRAKING.
1. INPUT SIGNALS
(1) SPEED SENSOR SIGNALTHE SPEED OF THE WHEELS IS DETECTED AND INPUT TO TERMINALS FL+, FR+, RL+ AND RR+ OF THE ABS ECU.
(2) STOP LIGHT SW SIGNAL A SIGNAL IS INPUT TO TERMINAL STP OF THE ABS ECU WHEN THE BRAKE PEDAL IS OPERATED.
(3) PARKING BRAKE SW SIGNAL A SIGNAL IS INPUT TO TERMINAL PKB OF THE ABS ECU WHEN THE PARKING BRAKE IS OPERATED.
2. SYSTEM OPERATION
DURING SUDDEN BRAKING, THE ABS ECU WHICH HAS SIGNALS INPUT FROM EACH SENSOR CONTROLS THE CURRENT FLOWING
TO THE SOLENOID INSIDE THE ACTUATOR AND LETS THE HYDRAULIC PRESSURE ACTING ON EACH WHEEL CYLINDER ESCAPE \
TO
THE RESERVOIR.
THE PUMP INSIDE THE ACTUATOR IS ALSO OPERATING AT THIS TIME AND IT RETURNS THE BRAKE FLUID FROM THE RESERVOIR
TO THE MASTER CYLINDER, THUS PREVENTING LOCKING OF THE VEHICLE WHEELS.
IF THE ECU JUDGES THAT THE HYDRAULIC PRESSURE ACTING ON THE WHEEL CYLINDER IS INSUFFICIENT, THE CURRENT
ACTING ON SOLENOID IS CONTROLLED AND THE HYDRAULIC PRESSURE IS INCREASED.
HOLDING OF THE HYDRAULIC PRESSURE IS ALSO CONTROLLED BY THE COMPUTER, BY THE SAME METHOD AS ABOVE. BY
REPEATED PRESSURE REDUCTION, HOLDING AND INCREASE ARE REPEATED TO MAINTAIN VEHICLE STABILITY AND TO IMPROVE
STEERABILITY DURING SUDDEN BRAKING.
A 4(B), A 33(A) ABS ACTUATOR
(A) 3, (A) 4±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 1±GROUND : ALWAYS CONTINUITY
(B) 4, (B) 5, (B) 6±GROUND : APPROX. 1.15
(IGNITION SW OFF)
(B) 2±GROUND :APPROX. 5
(IGNITION SW OFF)
A 7, A 8, A30, A31 ABS SPEED SENSOR FRONT LH, RH, REAR LH, RH
1±2 : APPROX. 1.0KW (20 °C, 68°F)
A22(A), A23(B) ABS ECU
(B) 11±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON
(B) 2, (B) 13±GROUND : ALWAYS CONTINUITY
(B) 22±GROUND : ALWAYS APPROX. 12 VOLTS
(B) 1, (A) 6, (A) 12±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON
(B) 16±GROUND : CONTINUITY WITH PARKING BRAKE LEVER PULLED UP
(B) 7±GROUND : APPROX. 12 VOLTS WITH STOP LIGHT SW ON
P 3 PARKING BRAKE SW
1±GROUND : CLOSED WITH PARKING BRAKE LEVER PULLED UP
S12 STOP LIGHT SW
1±2 : CLOSED WITH BRAKE PEDAL DEPRESSED
SYSTEM OUTLINE
SERVICE HINTS
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147
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A 4B26A3130D 228
A 726A33A26F 926
A 826B 126P 329
A22A28C 326S1229
A23B28C13B28T 629
A3030C14A28
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT624ENGINE COMPARTMENT LEFT
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1E20INSTRUMENT PANEL WIRE
1H20COWL WIRE1I20COWL WIRE
3A
3D22INSTRUMENT PANEL WIRE3E22INSTRUMENT 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)
IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)
IE238ENGINE ROOM MAIN WIRE AND COWL WIRE (BEHIND GLOVE BOX)
IG136INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)
IK136ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)IK236ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
IO138ENGINE ROOM MAIN WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
BW140ENGINE ROOM MAIN WIRE AND FLOOR NO. 3 WIRE (RIGHT KICK PANEL)
Bc240FLOOR NO. 3 WIRE AND FLOOR WIRE (UNDER THE LEFT SIDE OF REAR SEAT CUSHION)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EA34FRONT SIDE OF RIGHT FENDER
EB34FRONT SIDE OF LEFT FENDER
IJ36RIGHT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
E 934ENGINE ROOM MAIN WIREI2638ENGINE ROOM MAIN WIRE
E1034ENGINE ROOM MAIN WIREB1740FLOOR NO. 3 WIRE
E1234ENGINE ROOM MAIN WIREB3440FLOOR MAIN WIRE
I2338INSTRUMENT PANEL WIREB3640FLOOR NO. 3 WIRE
I2538ENGINE ROOM MAIN WIRE
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135
B
4 RL+
B
15 RL±
B
5 RSS
B
14 RR+
B
3 ALT
BW1
3BW1 8
BW1
2
BW1
5
BW1
6
Bc2
6
Bc2
2 I26
12 12
W O W±B
L±G
L±Y
W
O
L±G L±Y
W
O
L±G L±Y
(
SHIELDED ) (
SHIELDED )
(
SHIELDED )
REAR LH REAR RH A3 1
A3 0
ABS SPEED SENSOR
M
6
1
4
36
6
66
TRACTION BRAKE
MAIN RELAY
2 16 22
3
1 23 11
E7
I25 I32
I23
EB1
6
IO1
7 IK2
2
A
23
MTT A
1
TSR A
20
E2 A
19
VC A
10
PR A
15
SRC A
2
SMC A
12
SAC C
1
TS B
9
WA C
3
TC
A
1A 2A3
A
4A 5A6
B
2
B
1 B
4
L±Y
B±R
L
L
L
L VB±R
P±B
P±B B±R
R±W
R±W
R±W
W
R
B
V±Y V
V±W B±R
R
R±W
V±Y
TS WA
R
B±R
L±Y
W±B V±Y
W±B W±B P±B
L
TC
WB
T5 T3
,
T4C3
TRACTION PUMP
AND MOTOR TRACTI ON BRA KE
ACTUATOR
CHECK
CONNECTOR
BA
(
SHIELDED )
C
ABS AND TRACTION ECU A24 ,
A25 ,A26
AB P±B
P±B
ACC CUT MIC CUT
RESERVOIR
CUT
(
SHIELDED )
A
17 FR+
A
4 FR±
A
16 FS S
I26
21(
SHIELDED )
O±L
W±L W±B
W±L O±L
A8
FRONT RH B
8
IO1
10
3B
1
3B
2
IJ 1
5 IG3
1
A1 0
ALTERNATOR Y±G
Y±G
Y±G
Y±G
Y±G
RR±
I26
B17
BR
BR
I26
B34
BW1
7
Bc2
5 B17
B36
BR±B BR±B BR±B
BR±B
(
SHIELDED )
2
SHORT
PIN
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137
B±RR
G±W
LG±R W
L±Y
B±Y
V±R
P±G P±L
LG±B LG
GR L
R±B
R±W TRACTION E CUE9 , E10
AB
I33
I36 I36 2
IK2
15 EB1 5
1B
5
3A6
B
11
IND B
14
WT B
8
BAT B
2
STP
A
16
TR5 A
2
IG A
15
BM A
21
TR2 A
6
NEO A
8
VTH A
19
VSH
A
4 TRCO
A
5 THFA A
4 W
A
37 TR
A
38 NEO
A
40 VT01
A
39 VT02
B
6 TC
B
1 BRC
B
4 BRFA
B
10 FRO
B
3 FL O
B
7 P
B
16 N
B
15 ABSO
B
5 RLO
A
1 PKB
C
13 RRO
C
4 RLO
C
14 TRCO 1E
11
3B3
IJ2 12
IK2 4 IJ2
7
IK112
IK1 13 A
23 BRP
L±R
L±Y
Y±R P±L
V±Y Y±L
L±Y
W
LG±R
B±R R
G±W L±R
Y±R P±L
V±Y Y±L
P
R±W B±Y
V±R
P±G P±L
LG±B
LG
GR L
R±B
R±W P
R±W
L±YR
L±R
GRLG± R L
Y±B
LG±R
G±W
B±R
RR FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
7. 5A
TRAC
GR L
FROM A/T INDICATOR SW ENGINE AND ECT ECU
T1 3 ,T14
BA 13 14
I33 A
6
STP
G±W
G±W
B
12 RRO
P±B
P±B
IK2
13
3H
7
3F
2
R±W R±W
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138
ABS AND TRACTION CONTROL*1 : USA SPEC.
B
41 VC
B
43 VTA
B
64 IDL
B
46 THG
B
63 IDL2
B
44 THW
B
69 E1
A
26 BCM
A
25 B
A
24 B
A
11 A
A
12 A
A
13 ACM
A
14 GN D
A
20 E1
B
13 CSWA
10
IDL1 A
22
IDL2
1
2
3
4
VC VTA IDL E2 1
2
3
4
VC VTA IDL E2
E18
I32
E18
I37 I32
6 2
IF IJ ED
3H
14
1E
18 3A
1
1J
1 213645 BR
L±R RR±B
BR
BR
BRG
R±B R
Y
L±R
R±B R
BR
BR
R±B
Y±L BR
RY
L±R
Y
R L
W G
BR
W±B
BR
W±B
BR W±B
W±B
W±B
B+ B± B A A± A+
L±R
TO AI R FL OW
METER
(
VC )
FROM AIR FLOW
METER(
E2 )
THROTTLE POSITION
SENSOR SUBTHROTTLEPOSITION
SENSOR
IK2
16
Y±R
Y±R
S UB THROTTLE A CTUATOR
TRACTION
CUT SW TRACTION ECU
T12
S8
T1 3 , T 1 4
A B S9
T2 ENGINE AND ECT ECU E9
,E10
B A
IJ1
13
W±B (
SHIELDED )
E20 B
65 E2
BR
I32
B
42 VTA2
Y±LBR
1 2
1
2
BRE3
EGR GAS TEMP
SENSOR
EFI WATER
TEMP. SENSOR
A
3 S1
BR (
*1 )
(
*1 )
E2
±±
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139
(FOR ABS)
THIS SYSTEM CONTROLS THE RESPECTIVE BRAKE FLUID PRESSURES ACTING ON THE DISC\
BRAKE CYLINDERS OF THE RIGHT
FRONT WHEEL, LEFT FRONT WHEEL AND REAR WHEELS WHEN THE BRAKES ARE APPLIED IN \
A PANIC STOP SO THAT THE
WHEELS DO NOT LOCK. THIS RESULTS IN IMPROVED DIRECTIONALLY STABILITY AND STEERABILITY DURING PANIC BRAKING.
1. INPUT SIGNALS
(1) SPEED SENSOR SIGNALTHE SPEED OF THE WHEELS IS DETECTED AND INPUT TO TERMINALS FL+, FR+, RL+ AND RR+ OF THE ABS AND TRACTION
ECU.
(2) STOP LIGHT SW SIGNAL A SIGNAL IS INPUT TO TERMINAL STP OF THE ABS AND TRACTION ECU WHEN THE BRAKE PEDAL IS OPERATED.
(3) PARKING BRAKE SW SIGNAL A SIGNAL IS INPUT TO TERMINAL PKB OF THE ABS AND TRACTION ECU WHEN THE PARKING BRAKE IS OPERATED.
2. SYSTEM OPERATION
DURING SUDDEN BRAKING, THE ABS AND TRACTION ECU WHICH HAS SIGNALS INPUT FROM E\
ACH SENSOR CONTROLS THE
CURRENT FLOWING TO THE SOLENOID INSIDE THE ACTUATOR AND LETS THE HYDRAULIC PRESSURE ACTING ON EACH WHEEL
CYLINDER ESCAPE TO THE RESERVOIR. THE PUMP INSIDE THE ACTUATOR IS ALSO OPERATING AT THIS TIME AND IT RETURNS
THE BRAKE FLUID FROM THE RESERVOIR TO THE MASTER CYLINDER, THUS PREVENTING LOCKING OF THE VEHICLE WHEELS.
IF THE ECU JUDGES THAT THE HYDRAULIC PRESSURE ACTING ON THE WHEEL CYLINDER IS INSUFFICIENT, THE CURRENT
ACTING ON SOLENOID IS CONTROLLED AND THE HYDRAULIC PRESSURE IS INCREASED, HOLD\
ING OF THE HYDRAULIC
PRESSURE IS ALSO CONTROLLED BY THE COMPUTER, BY THE SAME METHOD AS ABOVE. BY REP\
EATED PRESSURE REDUCTION,
HOLDING AND INCREASE ARE REPEATED TO MAINTAIN VEHICLE STABILITY AND TO IMPROVE STEERABILITY DURING SUDDEN
BRAKING.
(FOR TRACTION CONTROL)
THE TRACTION CONTROL SYSTEM IS A SYSTEM WHEREBY THE ªABS AND TRACTION ECUº AND ªTRACTION ECUº\
CONTROLS THE
ENGINE TORQUE AND THE HYDRAULIC PRESSURE OF THE WHEEL CYLINDER OF THE DRIVING WHEELS IN ORDER TO CONTROL
SPINNING OF THE DRIVING WHEELS WHEN STARTING OFF AND ACCELERATING, AND PROVIDE THE MOST APPROPRIATE DRIVING
FORCE IN RESPONSE TO THE ROAD CONDITIONS FOR VEHICLE STABILITY.
TRACTION CONTROL OPERATION
VEHICLE SPEED SIGNALS FROM THE SPEED SENSOR INSTALLED ON EACH WHEEL ARE INPUT TO THE ABS AND TRACTION ECU.
WHEN THE ACCELERATOR PEDAL IS DEPRESSED WHILE DRIVING ON A SLIPPERY ROAD AND THE DRIVING WHEEL (REAR WHEEL)
SLIPS, IF THE ROTATION OF THE REAR WHEEL EXCEEDS THE ROTATION OF THE FRONT WHEELS FOR A SPECIFIED PERIOD, THE
ECU JUDGES THAT THE REAR WHEEL IS SLIPPING.
WHEN THIS OCCURS, CURRENT FLOWS FROM TRACTION ECU TO SUB THROTTLE ACTUATOR TO CLOSE THE SUB THROTTLE
VALVE. THE THROTTLE VALVE OPENING ANGLE SIGNAL IS OUTPUT FROM TERMINAL VTA OF SUB THROTTLE POSITION SENSOR
TO TERMINAL VTA2 OF ENGINE AND ECT ECU TO KEEP THE ENGINE RPM AT THE MOST SUITABLE LEVEL FOR THE DRIVING
CONDITIONS AND REDUCE SLIP OF THE DRIVING WHEEL. AT THE SAME TIME, OPERATION OF THE ABS AND TRACTION ECU
CAUSE THE TRACTION BRAKE ACTUATORS (ACC CUT, M/C CUT, RESERVOIR CUT SOLENOID) TO TURN ON TO SWITCH THE
HYDRAULIC CIRCUIT TO ªTRACTIONº MODE.
IN THIS CASE, SIGNALS ARE INPUT FROM TERMINAL SRR OF ABS AND TRACTION ECU TO TERMINAL (B)6 OF ABS ACTUATOR, AND
FROM TERMINAL SRL OF ABS AND TRACTION ECU TO TERMINAL (B)1 OF ABS ACTUATOR, CONTROLLING THE REAR WHEEL
SOLENOID IN THE ABS ACTUATOR AND INCREASING THE HYDRAULIC PRESSURE OF THE WHEEL CYLINDER IN ORDER \
TO
PREVENT SLIP.
TO MAINTAIN THE HYDRAULIC PRESSURE OF THE REAR WHEELS, THE REAR WHEEL SOLENOID I\
NSIDE THE ABS ACTUATOR IS
PUT IN ªHOLDº MODE AND KEEPS THE HYDRAULIC PRESSURE TO THE BRAKE CYLINDER CONSTANT.
WHEN THE BRAKE CYLINDER HYDRAULIC PRESSURE IS REDUCED, THE PRESSURE REDU\
CTION MODE REDUCES AND CONTROLS
THE HYDRAULIC PRESSURE.
SYSTEM OUTLINE
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141
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)1B20ENGINE ROOM MAIN WIRE1E20INSTRUMENT PANEL WIRE1H1I20COWL WIRE1J20COWL WIRE
3A3B3D22INSTRUMENT PANEL WIRE3E22INSTRUMENT PANEL WIRE
3F3H
: 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)IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)IE236ENGINE ROOM MAIN WIRE AND COWL WIRE (BEHIND GLOVE BOX)IG136INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)IG336INSTRUMENT PANEL WIRE AND COWL WIRE (RIGHT KICK PANEL)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)IK236ENGINE WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)
IO138ENGINE ROOM MAIN WIRE AND INSTRUMENT PANEL WIRE (RIGHT KICK PANEL)BW140ENGINE ROOM MAIN WIRE AND FLOOR NO. 3 WIRE (RIGHT KICK PANEL)Bc240FLOOR NO. 3 WIRE AND FLOOR WIRE (UNDER THE LEFT SIDE OF REAR SEAT CUSHION)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATIONEA34FRONT SIDE OF RIGHT FENDEREB34FRONT SIDE OF LEFT FENDERED34REAR SIDE OF INTAKE MANIFOLDIF36LEFT KICK PANELIJ36RIGHT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTSE 2I2338INSTRUMENT PANEL WIREE 7I2538ENGINE ROOM MAIN WIREE 934ENGINE ROOM MAIN WIRE
ENGINE ROOM MAIN WIREI2638ENGINE ROOM MAIN WIRE
E1034ENGINE ROOM MAIN WIRE
ENGINE ROOM MAIN WIREI32E12I33E13I3538ENGINE WIREE1834ENGINE WIREI3638ENGINE WIRE
E2034ENGINE WIREI37I 4B1740FLOOR NO. 3 WIREI 738COWL WIREB3440FLOOR MAIN WIREI1438COWL WIREB3640FLOOR NO. 3 WIREI1638INSTRUMENT PANEL WIRE
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226
AUTOMATIC AIR CONDITIONER
1. HEATER BLOWER MOTOR OPERATION
CURRENT IS APPLIED AT ALL TIMES THROUGH HEATER FUSE (60A) TO TERMINAL 5 OF HEATER RELAY. WHEN THE IGNITION SW IS
TURNED ON, CURRENT FLOWS THROUGH HEATER FUSE (10A) TO TERMINAL 1 OF HEATER RELAY " TERMINAL 3 " TERMINAL HR
OF A/C CONTROL ASSEMBLY. AT THE SAME TIME, CURRENT ALSO FLOWS FROM HEATER FUSE (10A) TO TERMINAL IG+ OF A/C
CONTROL ASSEMBLY AND TERMINAL 2 OF WATER VALVE VSV " TERMINAL 1 " TERMINAL WV OF A/C CONTROL ASSEMBLY.
* LOW SPEED OPERATION
WHEN THE BLOWER SW (A/C CONTROL ASSEMBLY) IS PUSHED TO LOW SPEED POSITION, THE CURRENT TO TERMINAL HR OF A/C
CONTROL ASSEMBLY FLOWS TO TERMINAL E OF A/C CONTROL ASSEMBLY " GROUND AND TURNS THE HEATER RELAY. AS A
RESULT, THE CURRENT TO TERMINAL 5 OF HEATER RELAY FLOWS TO TERMINAL 4 OF RELAY " TERMINAL 2 OF BLOWER
RESISTOR " TERMINAL 1 " GROUND AND CAUSES THE BLOWER MOTOR TO ROTATE AT LOW SPEED.
* MEDIUM (M1, M2, M3) AND HIGH SPEED OPERATION
WHEN THE BLOWER SW (A/C CONTROL ASSEMBLY) IS SELECTED TO MEDIUM (M1, M2, M3) OR HIGH POSITION, THE CURRENT TO
TERMINAL HR OF A/C CONTROL ASSEMBLY FLOWS TO TERMINAL E " GROUND AND TURNS THE HEATER RELAY ON. THEN, THE
CURRENT TO TERMINAL IG+ OF A/C CONTROL ASSEMBLY FLOWS TO TERMINAL BLR " TERMINAL (B)2 OF POWER TRANSISTOR
" TERMINAL (A)1 " GROUND. AS A RESULT, THE CURRENT TO TERMINAL 5 OF HEATER RELAY FLOWS TO TERMINAL 4 "
TERMINAL 2 OF BLOWER MOTOR " TERMINAL 1 " TERMINAL (A)2 OF POWER TRANSISTOR " TERMINAL (A)1 " GROUND AND
BLOWER MOTOR IS ROTATED AT SELECTED SPEED BY THE A/C CONTROL ASSEMBLY CONTROLLING THE CURRENT FLOW FROM
TERMINAL (B)2 OF POWER TRANSISTOR TO TERMINAL (B)1.
* AUTO FUNCTION
WHEN THE AUTO SW IN HEATER CONTROL SW (A/C CONTROL ASSEMBLY) IS SELECTED, THE CURRENT FLOW IS THE SAME AS
ABOVE MENTIONS, BUT THE A/C CONTROL ASSEMBLY DECIDES THE APPROPRIATE AIR FLOW VOLUME ACCORDING TO SET
TEMPERATURE AND THE INPUT SIGNALS FROM EACH SENSOR. BY CONTROLLING THE CURRENT FLOW\
FROM TERMINAL BLR OF
THE A/C CONTROL ASSEMBLY TO TERMINAL (B)2 OF POWER TRANSISTOR " TERMINAL (A)1 " GROUND , THE A/C CONTROL
ASSEMBLY CONTROLS THE BLOWER MOTOR STEPLESSLY.
2. OPERATION OF AIR INLET CONTROL SERVO MOTOR
(SWITCHING FROM FRESH TO RECIRC)
WITH IGNITION SW TURNED ON, THE CURRENT FLOWS FROM HEATER FUSE (10A) TO TERMINAL IG+ OF A/C CONTROL ASSEMBLY
" TERMINAL MREC " TERMINAL 6 OF AIR INLET CONTROL SERVO MOTOR " TERMINAL 2 " TERMINAL MFRS OF A/C CONTROL
ASSEMBLY " TERMINAL E " GROUND , THE MOTOR ROTATES AND THE DAMPER MOVES TO THE RECIRC SIDE. WHEN THE
DAMPER OPERATES WITH THE A/C SW AT RECIRC POSITION, THE DAMPER POSITION SIGNAL IS INPUT FROM TERMINAL 5 OF THE
SERVO MOTOR TO TERMINAL TPI OF THE ECU (BUILT INTO THE A/C CONTROL ASSEMBLY). AS A RESULT, CURRENT TO THE SERVO
MOTOR CIRCUIT IS CUT OFF BY THE ECU, SO THE DAMPER STOPS AT THAT POSITION.
(SWITCHING FROM RECIRC TO FRESH)
WITH IGNITION SW TURNED ON, WHEN THE RECIRC/FRESH SW IS SWITCHED TO THE FRESH SIDE, THE CURRENT FLOWS FROM
TERMINAL IG+ OF A/C CONTROL ASSEMBLY " TERMINAL MFRS " TERMINAL 2 OF AIR INLET CONTROL SERVO MOTOR "
TERMINAL 6 " TERMINAL MREC OF A/C CONTROL ASSEMBLY " TERMINAL E " GROUND , THE MOTOR ROTATES AND THE
DAMPER STOPS AT THAT POSITION.
3. OPERATION OF AIR VENT MODE CONTROL SERVO MOTOR
WITH IGNITION SW TURNED ON, THE CURRENT FLOWS FROM HEATER FUSE (10A) TO TERMINAL IG+ OF A/C CONTROL ASSEMBLY.
(SWITCHING FROM DEF TO FACE)
THE CURRENT FLOWS FROM TERMINAL MFACE OF A/C CONTROL ASSEMBLY " TERMINAL 4 OF AIR VENT CONTROL SERVO
MOTOR " TERMINAL 5 " TERMINAL MDEF OF A/C CONTROL ASSEMBLY " TERMINAL E " GROUND . THE MOTOR ROTATES AND
THE DAMPER MOVES TO THE FACE SIDE. WHEN THE DAMPER OPERATES WITH THE A/C SW AT FACE POSITION, THE DAMPER
POSITION SIGNAL IS INPUT FROM TERMINAL 1 OF THE SERVO MOTOR TO THE TERMINAL TPM OF THE ECU (BUILT INTO THE A/C
CONTROL ASSEMBLY). AS A RESULT, CURRENT TO THE SERVO MOTOR CIRCUIT IS CUT OFF BY THE ECU, SO THE DAMPER STOPS
AT THAT POSITION.
(SWITCHING FROM FACE TO DEF)
THE CURRENT FLOWS FROM TERMINAL DEF OF A/C CONTROL ASSEMBLY " TERMINAL 5 OF AIR VENT CONTROL SERVO MOTOR
" TERMINAL 4 " TERMINAL MFACE OF A/C CONTROL ASSEMBLY " TERMINAL E " GROUND , THE MOTOR ROTATES AND THE
DAMPER STOPS AT THAT POSITION.
SYSTEM OUTLINE
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