ignition LEXUS SC300 1991 Service Repair Manual

61
A10(A) ALTERNATOR
(A) 1±GROUND : 13.9±15.1 VOLTS WITH ENGINE RUNNING AT 2000 RPM AND 25°C ( 77°F)
13.5±14.3 VOLTS WITH ENGINE RUNNING AT 5000 RPM AND 11 5°C ( 239 °F)
(A) 2±GROUND : 0±4 VOLTS WITH IGNITION SW AT ON POSITION AND ENGINE NOT RUNNING
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A10A26C1228
A11B26F 926
: 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
1H20COWL WIRE
3D22INSTRUMENT PANEL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
EB234ENGINE 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)
IG338INSTRUMENT PANEL WIRE AND COWL WIRE (RIGHT KICK PANEL)
IJ136ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)IJ236ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I1438COWL WIRE
X X
14 15 6 5
7
1
23 1
B
A
A10 A11 C12 F 9 BLACK BLACK
SERVICE HINTS
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CIGARETTE LIGHTER
1E
2
3A5
3F5
3F8
1E18
3A 1
1J1
IF
FROM POWER SOUR CE SYSTEM
(
SEE PAGE 56 )
15A
CIG
CIGARETTE
LIGHTER C11
L±R L±R
W±B W±B
W±B
4 2
C11 CIGARETTE LIGHTER
2±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ACC OR ON POSITION
4±GROUND : ALWAYS CONTINUITY
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C1128
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1E20INSTRUMENT PANEL WIRE
1J20COWL WIRE
3A23INSTRUMENT PANEL WIRE3F23INSTRUMENT PANEL WIRE
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
2
4
C11
BLUE
SERVICE HINTS
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COMBINATION METER
B 1 BRAKE FLUID LEVEL SW
1±2 : CLOSED WITH FLOAT DOWN
P 3 PARKING BRAKE SW
1±GROUND : CLOSED WITH PARKING BRAKE LEVER PULLED UP
O 2 OIL PRESSURE SW
1±GROUND : CLOSED WITH OIL PRESSURE BELOW APPROX. 0.2 KG/CM2 (2.8 PSI, 20 KPA)
W 3 WATER TEMP. SENDER
1±GROUND : APPROX. 226
(50 °C, 122 °F)
APPROX. 25
(11 5 °C, 239 °F)
E 6 ENGINE OIL LEVEL WARNING SW
1±2 : CLOSED WITH FLOAT UP AND ENGINE OIL TEMP. AT BELOW APPROX. 55°C ( 131 °F)
OPEN WITH FLOAT DOWN AND ENGINE OIL TEMP. AT BELOW APPROX. 60°C ( 140 °F)
F18(A) FUEL SENDER
2±3 : APPROX. 3
AT FUEL FULL
APPROX. 11 0
AT FUEL EMPTY
C14 (C) COMBINATION METER
1±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
12±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ST POSITION AND SHIFT LEVER AT P OR N RANGE
10±GROUND : ALWAYS CONTINUITY
22±GROUND : ALWAYS CONTINUITY
11±GROUND : ALWAYS APPROX. 12 VOLTS
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A1026E 626R 929
B 126F17B30S 327
C12A28F18A30S22B29
C13B28I 227S23A29
C14C28I16A29T1529
D 128O 227W 127
D 228P 329W 327
: 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
IE20INSTRUMENT PANEL WIRE
1G20COWL NO. 2 WIRE
1H
1I20COWL WIRE1J20COWL WIRE
1K
3A
3B
3C
3D22INSTRUMENT PANEL WIRE
3E
3F
3H
SERVICE HINTS
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Position of Parts in Engine Compartment
I 1 ISC Valve S 3Speed Sensor No. 1
I 2 Igniter S 4 Speed Sensor No. 2 (for ECT)
I 4 Ignition Coil S 6 Starter
I 6 Injector No. 1 S 7 Starter
I 7 Injector No. 2 S 8 Sub Throttle Actuator
I 8 Injector No. 3 S 9 Sub Throttle Position Sensor
I 9 Injector No. 4
I 10 Injector No. 5 T 1 Theft Deterrent Horn
I 11 Injector No. 6 T 2 Throttle Position Sensor T 3 Traction Brake Actuator
K 1 Knock Sensor No. 1 (on Front Side) T 4 Traction Brake Actuator
K 2 Knock Sensor No. 2 (on Rear Side) T 5 Traction pump and Motor
N 1 Neutral Start SW, Back±Up Light SW and A/T Indicator SW V 1 VSV (for EGR) (Exc. USA Spec) (for A/T) V 2 VSV (for EVAP)
N 2 Noise Filter (for Defogger System) V 4 VSV (for Water Valve)
N 3 Noise Filter (for Ignition System) V 7 VSV (for Intake Control Valve)
O 2 Oil Pressure SW W 1 Washer Level SW
O 3 Oxygen Sensor Main No. 1 (on Front Side) W 2 Washer Motor
O 4 Oxygen Sensor Main No. 2 (on Rear Side) W 3 Water Temp. Sender W 5 Wiper Motor
P 1 PPS Solenoid
P 20 Power Steering Pressure SW
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Position of Parts in Instrument Panel
H 7 Hazard SW S 10 Shift Lock ECUS 11 Step Light
I 14 Ignition Key Cylinder Light S 12 Stop Light SW
I 15 Ignition SW, Unlock Warning SW and Key Inter Lock Solenoid S 22 Short Connector
I 16 Integration Relay S 23 Short Connector S 24 Seat Heater SW (for M/T)
K 3 Kick Down SW T 6 TDCL (Total Diagnostic Communication Link)
L 1 Luggage Compartment Door Open SW T 7 Telescopic Position Sensor T 8 Theft Deterrent and Door Lock Control ECU
N 4 Noise Filter (for A/C System) T 9 Theft Deterrent and Door Lock Control ECU T 10 Tilt and Power Telescopic ECU
O 5 O/D Main SW T 11 Tilt and Power Telescopic ECU T 12 Traction Cut SW and Seat Heater SW (for A/T)
P 2 PPS ECU T 13 Traction ECU (for A/T)
P 3 Parking Brake SW T 14 Traction ECU (for A/T) T 15 Trip SW and Theft Deterrent Indicator Light
R 2 Radio and Player
R 3 Radio and Player W 6 Water Temp. Sensor (for A/C System)
R 4 Radio and Player (w/ CD Player) W 7 Wireless Door Lock Main SW
R 5 Radio and Player (w/o CD Player)
R 6 Radio and Player (w/o CD Player)
R 7 Remote Control Mirror ECU
R 8 Remote Control Mirror ECU
R 9 Rheostat
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CRUISE CONTROL
CURRENT IS APPLIED AT ALL TIMES THROUGH STOP FUSE TO TERMINAL 1 OF THE CONTROL ECU TERMINAL 2 OF STOP LIGHT
SWITCH, AND ALSO THROUGH THE DOME FUSE TO TERMINAL 15 OF CRUISE CONTROL ECU.
WITH THE IGNITION SWITCH TURNED TO ON, THE CURRENT FLOWS THROUGH GAUGE FUSE TO TERMINAL (A)1 OF COMBINATION
METER AND THE CURRENT THROUGH ECU±IG FUSE FLOWS TO TERMINAL 14 OF CRUISE CONTROL ECU.
WHEN THE IGNITION SWITCH IS ON AND THE CRUISE CONTROL MAIN SWITCH IS TUR\
NED ON, A SIGNAL IS INPUT FROM TERMINAL
15 OF CRUISE CONTROL MAIN SWITCH TO TERMINAL 4 OF CRUISE CONTROL ECU. AS A RESULT, THE CRUISE CONTROL ECU
FUNCTIONS AND THE CURRENT TO TERMINAL 14 OF CRUISE CONTROL ECU TO TERMINAL 13 OF CRUISE CONTROL ECU "
GROUND, AND THE CRUISE CONTROL SYSTEM IS IN A CONDITION READY FOR OPERATION.
AT THE SAME TIME, THE CURRENT THROUGH THE GAUGE FUSE FLOWS FROM TERMINAL (A)1 OF CRUISE CONTROL INDICATOR
LIGHT " TERMINAL (B)20 "TERMINAL 5 OF CRUISE CONTROL ECU "TERMINAL 13 " TO GROUND, CAUSING THE CRUISE
CONTROL INDICATOR LIGHT TO LIGHT UP, INDICATING THAT THE CRUISE CONTROL IS READY FOR OPERATION.
1. SET OPERATION
WHEN THE CRUISE CONTROL MAIN SWITCH IS TURNED ON AND THE SET SWITCH IS PUSHE\
D WITH THE VEHICLE SPEED WITHIN
THE SET LIMIT (APPROX. 40 KM/H, 2.5 MPH TO 200 KM/H, 124 MPH), A SIGNAL IS INPUT TO TERMINAL 18 OF THE CRUISE CONTROL
ECU AND THE VEHICLE SPEED AT THE TIME THE SET SWITCH IS RELEASED IS MEMORIZED IN THE ECU AS THE SET\
SPEED.
2. SET SPEED CONTROL
DURING CRUISE CONTROL DRIVING, THE ECU COMPARES THE SET SPEED MEMORIZED IN THE ECU WITH THE ACTUAL VEHICLE
SPEED INPUT INTO TERMINAL 20 OF THE CRUISE CONTROL ECU FROM THE SPEED SENSOR, AND CONTROLS THE CRUIS\
E
CONTROL ACTUATOR TO MAINTAIN THE SET SPEED.
WHEN THE ACTUAL SPEED IS LOWER THAN THE SET SPEED, THE ECU CAUSES THE CURREN\
T TO THE CRUISE CONTROL
ACTUATOR TO FLOW FROM TERMINAL 12 " TERMINAL 6 OF CRUISE CONTROL ACTUATOR "TERMINAL 7 " TERMINAL 11 OF
CRUISE CONTROL ECU. AS A RESULT, THE MOTOR IN THE CRUISE CONTROL ACTUATOR IS ROTATED TO OPEN THE THROTTLE
VALVE AND THE THROTTLE CABLE IS PULLED TO INCREASE THE VEHICLE SPEED. WHEN THE ACTUAL DRIVING SPEED IS HIGHER
THAN THE SET SPEED, THE CURRENT TO CRUISE CONTROL ACTUATOR FLOWS FROM TERMINAL 11 OF ECU "TERMINAL 7 OF
CRUISE CONTROL ACTUATOR "TERMINAL 6 "TERMINAL 12 OF CRUISE CONTROL ECU.
THIS CAUSES THE MOTOR IN THE CRUISE CONTROL ACTUATOR TO ROTATE TO CLOSE THE THROTTLE VALVE AND RETURN THE
THROTTLE CABLE TO DECREASE THE VEHICLE SPEED.
3. COAST CONTROL
DURING THE CRUISE CONTROL DRIVING, WHILE THE COAST SWITCH IS ON, THE CRUISE CONTROL ACTUATOR RETURNS THE
THROTTLE CABLE TO CLOSE THE THROTTLE VALVE AND DECREASE THE DRIVING SPEED. THE VEHICLE SPEED WHEN THE COAST
SWITCH IS TURNED OFF IS MEMORIZED AND THE VEHICLE CONTINUES AT THE NEW SET SPEED.
4. ACCEL CONTROL
DURING CRUISE CONTROL DRIVING, WHILE THE ACCEL SWITCH IS TURNED ON, THE CRUISE\
CONTROL ACTUATOR PULLS THE
THROTTLE CABLE TO OPEN THE THROTTLE VALVE AND INCREASE THE DRIVING SPEED.
THE VEHICLE SPEED WHEN THE ACCEL SWITCH IS TURNED OFF IS MEMORIZED AND THE \
VEHICLE CONTINUES AT THE NEW SET
SPEED.
5. RESUME CONTROL
UNLESS THE VEHICLE SPEED FALLS BELOW THE MINIMUM SPEED LIMIT (APPROX. 40 KM/H, 25 MPH) AFTER CANCELING THE SET
SPEED BY THE CANCEL SWITCH, PUSHING THE RESUME SWITCH WILL CAUSE THE VEHICLE \
TO RESUME THE SPEED SET BEFORE
CANCELLATION.
6. MANUAL CANCEL MECHANISM
IF ANY OF THE FOLLOWING OPERATIONS OCCURS DURING CRUISE CONTROL OPERATION, THE SAFETY MAGNETIC CLUTCH OF
THE ACTUATOR TURNS OFF AND THE MOTOR ROTATES TO CLOSE THE THROTTLE VALVE AND THE CRUISE CONTROL IS
RELEASED.
* PLACING THE SHIFT LEVER IN ªNº RANGE (NEUTRAL START SWITCH ON)). ªSIGNAL INPUT TO TERMINAL 2 OF ECUº
* DEPRESSING THE BRAKE LEVER (STOP LIGHT SWITCH ON). ªSIGNAL INPUT TO TERMINAL 16 OF ECUº
* PULLING THE PARKING BRAKE PEDAL (PARKING BRAKE SWITCH ON). ªSIGNAL INPUT TO TERMINAL 3 OF ECUº
* PUSHING THE CANCEL SWITCH (CANCEL SWITCH ON). ªSIGNAL INPUT TO TERMINAL 18ª
SYSTEM OUTLINE
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151
7. AUTO CANCEL FUNCTION
A) IF ANY OF THE FOLLOWING OPERATING CONDITIONS OCCURS DURING CRUISE CONTROL OPERATION, THE SET SPEED IS
ERASED, CURRENT FLOW TO MAGNETIC CLUTCH IS STOPPED AND THE CRUISE CONTROL IS RELEASED. (MAIN SWITCH TURNS
OFF).
WHEN THIS OCCURS, THE IGNITION SWITCH MUST BE TURNED OFF ONCE BEFORE THE MAI\
N SWITCH WILL TURN ON.* OVER CURRENT TO TRANSISTER DRIVING MOTOR AND/OR MAGNETIC CLUTCH.
* WHEN CURRENT CONTINUED TO FLOW TO THE MOTOR INSIDE THE ACTUATOR IN THE THROTTLE VALVE ªOPENº DIRECTION.
* OPEN CIRCUIT IN MAGNETIC CLUTCH.
* MOMENTARY INTERRUPTION OF VEHICLE SPEED SIGNAL.
* SHORT CIRCUIT IN CRUISE CONTROL SWITCH.
* MOTOR DOES NOT OPERATE DESPITE THE MOTOR DRIVE SIGNAL BEING OUTPUT.
B) IF ANY OF THE FOLLOWING CONDITIONS OCCURS DURING CRUISE CONTROL OPERATION, THE SET SPEED IS ERASED AND
THE CRUISE CONTROL IS RELEASED. (THE POWER OF MAGNETIC CLUTCH IS CUT OFF U\
NTIL THE SET SWITCH IS ªONº AGAIN.) * WHEN THE VEHICLE SPEED FALLS BELOW THE MINIMUM SPEED LIMIT, APPROX. 40 KM/H ( 2.5 MPH)
* WHEN THE VEHICLE SPEED FALLS MORE THAN 16 KM/H ( 10 MPH) BELOW THE SET SPEED, E.G. ON AN UPWARD SLOPE.
* WHEN POWER TO THE CRUISE CONTROL SYSTEM IS MOMENTARILY CUT OFF.
C) IF ANY OF THE FOLLOWING CONDITIONS OCCURS DURING CRUISE CONTROL OPERATION, THE CRUISE CONTROL IS
RELEASED.
* OPEN CIRCUIT FOR TERMINAL 1 OF CRUISE CONTROL ECU AND SPLICE POINT ªI 9º.
8. AUTOMATIC TRANSMISSION CONTROL FUNCTION
*IN OVERDRIVE. IF THE VEHICLE SPEED BECOMES LOWER THAN THE OVERDRIVE CUT SPEED (SET SPEED MINUS APPROX. 4
KM/H, 2.5 MPH) DURING CRUISE CONTROL OPERATION, SUCH AS DRIVING UP A HILL, THE OVERDRIVE IS RELEASED AND THE
POWER INCREASED TO PREVENT A REDUCTION IN VEHICLE SPEED.
* AFTER RELEASING THE OVERDRIVE, VEHICLE SPEED BECOMES HIGHER THAN THE OVE\
RDRIVE RETURN SPEED (SET SPEED
MINUS APPROX. 2 M/H, 1.2 MPH) AND THE ECU JUDGES BY THE SIGNALS FROM POTENTIOMETER OF THE ACTUATOR THAT THE
UPWARD SLOPE HAS FINISHED, OVERDRIVE IS RESUMED AFTER APPROXIMATELY 6 SECONDS.
* DURING CRUISE CONTROL DRIVING, THE CRUISE CONTROL OPERATION SIGNAL IS OUTPUT FROM THE CRUISE CONTROL
ECU TO THE ENGINE AND TRANSMISSION ECU. UPON RECEIVING THIS SIGNAL, THE ENGIN\
E AND TRANSMISSION ECU
CHANGES THE SHIFT PATTERN TO NORMAL.
TO MAINTAIN SMOOTH CRUISE CONTROL OPERATION (ON A DOWNWARD SLOPE ETC.), LOCK±UP RELEASE OF THE
TRANSMISSION WHEN THE IDLING POINT OF THE THROTTLE POSITION IS ªONº IS FORBIDD\
EN.
C 8 CRUISE CONTROL ACTUATOR
1±3 : APPROX. 2K

5±4 : APPROX. 38.5

C15 CRUISE CONTROL SW [COMB. SW]
15±6 :CONTINUITY WITH MAIN SW ON
5±6 :APPROX. 420
WITH CANCEL SW ON
APPROX. 70
WITH RESUME/ACCEL SW ON
APPROX. 200
WITH SET/COAST SW ON
C19 CRUISE CONTROL ECU
14±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
1, 15±GROUND : ALWAYS APPROX. 12 VOLTS
3±GROUND : CONTINUITY WITH PARKING BRAKE LEVER PULLED UP (ONE OF THE CANCEL SW) OR BRAKE LEVER WARNING SW ON
20±GROUND : 1 PULSE WITH 40CM (DRIVER VEHICLE SLOWLY)
18±GROUND : APPROX. 420
WITH CANCEL SW ON IN CONTROL SW
APPROX. 200
WITH SET/COAST SW ON IN CONTROL SW
APPROX. 70
WITH RESUME/ACCEL SW ON IN CONTROL SW
13±GROUND : ALWAYS CONTINUITY
SERVICE HINTS
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E 1 ECT SOLENOID
1±4 : APPROX. 5.3

2±5 : APPROX. 3.7

3±GROUND : APPROX. 13.2

6±GROUND : APPROX. 13.2

E 2 EFI WATER TEMP. SENSOR
1±2 : APPROX. 16.2K
( ±20 °C ±4 °F)
APPROX. 2.5K
( 20 °C 68 °F)
APPROX. 0.32K
( 80 °C 176 °F)
E 8 ECT PATTERN SELECT SW
4±3 : CLOSED WITH ECT PATTERN SELECT SW AT POWER POSITION
E 9(A), E10(B) ENGINE AND ECT ECU
BATT ± E1: ALWAYS APPROX. 12 VOLTS
IGSW ± E1: APPROX. 12 VOLTS WITH IGNITION SW ON
BK ± E1: APPROX. 12 VOLTS WITH BRAKE PEDAL DEPRESSED
P ± E1: APPROX. 12 VOLTS WITH IGNITION SW ON POSITION AND ECT PATTERN SELECT SW AT POWER POSITION
KD±GROUND :CONTINUITY WITH KICK DOWN SW ON
OD2 ± E1: APPROX. 12 VOLTS WITH O/D MAIN SW ON
0 VOLTS WITH O/D MAIN SW ON
+B±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
+B1±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
MREL±GROUND:APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
E01±GROUND : ALWAYS CONTINUITY
E02±GROUND : ALWAYS CONTINUITY
L±GROUND : APPROX. 12 VOLTS WITH SHIFT LEVER AT ªLº RANGE
2±GROUND : APPROX. 12 VOLTS WITH SHIFT LEVER AT ª2º RANGE
R±GROUND : APPROX. 12 VOLTS WITH SHIFT LEVER AT ªRº RANGE
E1±GROUND : ALWAYS CONTINUITY
VC±VTA1 : LESS THAN 1 VOLTS WITH THROTTLE VALVE FULLY CLOSED
MORE THAN 3 VOLTS WITH THROTTLE VALVE OPEN
VTA1 ± E2: CONTINUITY WITH THROTTLE VALVE FULLY CLOSED APPROX. 4K
WITH THROTTLE VALVE FULLY OPEN
VC ± E2: APPROX. 5 VOLTS
O 1 O/D DIRECT CLUTCH SPEED SENSOR
1±2 : APPROX. 620

S 4 SPEED SENSOR NO.2 (FOR ECT)
1±2 : APPROX. 620

S12 STOP LIGHT SW
2±1 : CLOSED WITH BRAKE PEDAL DEPRESSED
SERVICE HINTS
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.
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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2. CONTROL SYSTEM
*EFI (ELECTRONIC FUEL INJECTION) SYSTEM
THE EFI SYSTEM MONITORS THE ENGINE CONDITION THROUGH THE SIGNALS INPUT FROM EACH SENSOR (IN\
PUT SIGNALS
FROM (1) TO (13) ETC.) TO THE ECU. THE BEST FUEL INJECTION TIMING IS DECIDED BASED ON THIS DATA AND THE PROGRAM
MEMORIZED BY THE ECU, AND THE CONTROL SIGNAL IS OUTPUT TO TERMINALS #10, #20, #30, #40, #50 AND #60 OF THE ECU TO
OPERATE THE INJECTOR. (INJECT THE FUEL). THE EFI SYSTEM PRODUCES CONTROL OF FUEL INJECTION OPERATION BY THE
ECU IN RESPONSE TO THE DRIVING CONDITIONS.
* ESA (ELECTRONIC SPARK ADVANCE) SYSTEM
THE ESA SYSTEM MONITORS THE ENGINE CONDITION THROUGH THE SIGNALS INPUT TO THE ECU FROM EACH SENSOR (INPUT
SIGNALS FROM (1), (2), (4) TO (13) ETC.). THE BEST IGNITION TIMING IS DECIDED ACCORDING TO THIS DATA AND THE
MEMORIZED DATA IN THE ECU AND THE CONTROL SIGNAL IS OUTPUT TO TERMINAL IGT THIS SIGNAL CONTROLS THE IGNITER
TO PROVIDE THE BEST IGNITION TIMING FOR THE DRIVING CONDITIONS.
* OXYGEN SENSOR HEATER CONTROL SYSTEM (USA SPEC.)
THE OXYGEN SENSOR HEATER CONTROL SYSTEM TURNS THE HEATER ON WHEN THE INTAKE AIR VOLUME IS LOW (TEMP. OF
EXHAUST EMISSIONS IS LOW), AND WARMS UP THE OXYGEN SENSOR TO IMPROVE DETECTION PERFORMANCE OF THE
SENSOR.
THE ECU EVALUATES THE SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM (1), (2), (4)\
, (9) TO (11) ETC.,) AND OUTPUTS
CURRENT TO TERMINAL HT TO CONTROL THE HEATER.
* ISC (IDLE SPEED CONTROL) SYSTEM
THE ISC SYSTEM (STEP MOTOR TYPE) INCREASES THE RPM AND PROVIDES IDLING STABILITY FOR FAST IDLE±UP WHEN THE
ENGINE IS COLD, AND WHEN THE IDLE SPEED HAS DROPPED DUE TO ELECTRICAL LOAD AND SO ON. THE ECU EVALUATES
THE SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM (1), (4), (5), (8)\
, (9), (11) ETC.), OUTPUTS CURRENT TO TERMINAL ISC1,
ISC2, ISC3 AND ISC4 TO CONTROL ISC VALVE.
* EGR CONTROL SYSTEM
THE EGR CONTROL SYSTEM DETECTS THE SIGNAL FROM EACH SENSOR (INPUT SIGNALS \
FROM (1), (4), (9), (10) ETC.), AND
OUTPUTS CURRENT TO TERMINAL EGR TO CONTROL THE EGR VALVE.
* FUEL PUMP CONTROL SYSTEM
THE COMPUTER OUTPUTS CURRENT TO TERMINAL FPC AND CONTROLS THE FUEL PUMP ECU AND FUEL PUMP DRIVE SPEED
IN RESPONSE TO CONDITIONS.
* ACIS (ACOUSTIC CONTROL INDUCTION SYSTEM)
ACIS INCLUDES A VALVE IN THE BULKHEAD SEPARATING THE SURGE TANK INTO TWO PARTS. THIS VALE IS OPENED AND
CLOSED IN ACCORDANCE WITH THE DRIVING CONDITIONS TO CONTROL THE INTAKE MANIFOLD LENGTH IN TWO STAGES FOR
INCREASED ENGINE OUTPUT IN ALL RANGES FROM LOW TO HIGH SPEEDS.
THE ECU JUDGES THE VEHICLE SPEED BY THE SIGNALS ((4), (5)) FROM EACH \
SENSOR AND OUTPUTS SIGNALS TO THE
TERMINAL ACIS TO CONTROL THE VSV (FOR OPENING AND CLOSING THE INTAKE CONTROL VALVE).
3. DIAGNOSIS SYSTEM
WITH THE DIAGNOSIS SYSTEM, WHEN THERE IS A MALFUNCTION IN THE ECU SIGNAL\
SYSTEM, THE MALFUNCTIONING SYSTEM IS
RECORDED IN THE MEMORY. THE MALFUNCTIONING SYSTEM CAN BE FOUND BY READING THE CODE DISPLAYED BY THE
CHECKING ENGINE WARNING LIGHT.
4. FAIL±SAFE SYSTEM
WHEN A MALFUNCTION HAS OCCURRED IN ANY SYSTEM, IF THERE IS A POSSIBILITY OF \
ENGINE TROUBLE BEING CAUSED BY
CONTINUED CONTROL BASED ON THE SIGNALS FROM THAT SYSTEM, THE FAIL±SAFE SYSTEM EITHER CONTROLS THE SYSTEM
BY USING DATA (STANDARD VALUES) RECORDED IN THE ECU MEMORY OR ELSE STOPS THE ENGINE.
NOTE: THE SPECIFICATION DESCRIPTIONS ªUSA SPEC.º AND ªEXC. USA SPEC.º USED IN THIS SECTION INDICATE THE
FOLLOWING SPECIFICATIONS.
USA SPEC. : USA (50 STATES) SPECIFICATIONS
EXC. USA SPEC. : USA (EXCEPT CALIFORNIA) AND CANADIAN SPECIFICATIONS.
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