1991 LEXUS SC400 Throttle Position

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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ABS AND TRACTION CONTROL
A24(A), A25(B), A26(C) ABS AND TRACTION ECU
(B) 21±GROUND : ALWAYS APPROX. 12 VOLTS
(B) 11±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
(B) 10±GROUND : CONTINUITY WITH STOP LIGHT SW ON
(B) 2, (B) 13, (B) 22±GROUND : ALWAYS CONTINUITY
(B) 17±GROUND : CONTINUITY WITH PARKING BRAKE LEVER PULLED UP (PARKING BRAKE SW ON)
A 4(B), A 5(C), A 6(A) ABS ACTUATOR
(A) 1, (A) 2±GROUND : APPROX. APPROX. 12 VOLTS
(C) 1±GROUND : ALWAYS CONTINUITY
(B) 1, (B) 5, (B) 4, (B) 6±GROUND : APPROX. 1.15 (IGNITION SW OFF)
(B) 2±GROUND : APPROX. 5 (IGNITION SW OFF)
T3(A), T 4(B) TRACTION BRAKE ACTUATOR
(B) 2± (B) 4 : OPEN ABOVE APPROX. 134.5KG/CM2
(13189 KPA, 1910PSI)
CLOSED BELOW APPROX. 95KG/CM2 (9316 KPA, 1349PSI)
(A) 3± (A) 6 : APPROX. 2
(A) 2± (A) 5 : APPROX. 2
(A) 1± (A) 4 : APPROX. 2
S12 STOP LIGHT SW
2±1 : CLOSED WITH BRAKE PEDAL DEPRESSED
A 7, A 8, A30, A31 ABS SPEED SENSOR FRONT LH, RH, REAR LH, RH
1±2 : APPROX. 1.0(20 °C, 68°F)
T13(B), T14(A) TRACTION ECU
(A) 2±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
(A) 15±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 20, (A)14±GROUND : ALWAYS CONTINUITY
(A) 1±GROUND : CONTINUITY WITH PARKING BRAKE LEVER PULLED UP
(B) 2±GROUND : APPROX. 12 VOLTS WITH STOP LIGHT SW ON
(B) 13±GROUND : CONTINUITY WITH TRACTION CUT SW PUSHED ON
(B) 8±GROUND : ALWAYS APPROX. 12 VOLTS
P 3 PARKING BRAKE SW
1±GROUND : CLOSED WITH PARKING BRAKE LEVER PULLED UP
S 8 SUB THROTTLE ACTUATOR
2±1, 2±3 : APPROX. 0.9
5±4, 5±6 : APPROX. 0.9
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
A 4B26C 326S 927
A 5C26C13B28S1229
A 6A26C14A28T 227
A 726D 128T 3A27
A 826D 228T 4B27
A1026E 226T 527
A24A28E 326T 629
A25B28E 9A28T1229
A26C28E10B28T13B29
A3030F 926T14A29
A3130P 329
B 126S 827
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT624ENGINE COMPARTMENT LEFT
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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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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2 1
2
1
E18 E20
E20 I32
I32
B
27 B
4B 28 A20 B 29
B
42 B 63 B 41 B43 B64 B65 B 44 B 23 B3
ED
E18
L±R
Y±L
R±B
BR
L±R Y
R BR
BR
Y±L
R±B
L±R Y
R
BR
G
P
V
GR±Y LG
B±Y BR
LG
BR
W±B
BR L
LG
GR±Y
BR
L±R
GR±Y
14 8 13
3
NE
E11 VF2 TE1 VF1
VTA2 IDL2 VC VTA1 IDL1 E2 THW SP2 SP2±
G1 TVF1
E1
SUBTHROTTLEPOSITION
SENSOR
(
W/ TRACTION CONTROL ) THROTTLE POSITION SENSOR
EFI WATER
TEMP. SENSOR
SPEED SENSOR
NO. 2(
FOR ECT )
ENGINE AND ECT ECU
CHE CK CONNE CTOR
VC VTA IDL2 E2 VC VTA IDL E2
4321 4321
C3
S4
E2
T2
S9
B
E9
,E10
A
P
(
W/ TRACTION CONTROL )
( W/ TRACTION CONTROL )
( W/ TRACTION CONTROL )
( W/ TRACTION
CONTROL )
BR
B
26
R
G1
B
25
Y
G2
B
7
B
G±
VF2
NE
G±
G2 B
79
W±B
EO2
B
80
W±B
EO1
I33 I33 B
69
BR
E1
W±B W±B
2341
D13
DISTRIBUTOR
BR
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130
ECT AND A/T INDICATOR
THIS SYSTEM, ELECTRICALLY CONTROLS THE LINE PRESSURE, THROTTLE PRESSURE, LOCK±UP PRESSURE AND\
ACCUMULATOR
PRESSURE ETC. THROUGH THE SOLENOID VALVE. THE ECT IS A SYSTEM WHICH PRECISELY CONTROLS GEAR SHIFT TIMING AND
LOCK±UP TIMING IN RESPONSE TO THE VEHICLE'S DRIVING CONDITIONS AND THE ENGINE OPERATING CONDITIONS DETECTED
BY VARIOUS SENSORS, MAKING SMOOTH DRIVING POSSIBLE BY SHIFT SELECTION FOR EA\
CH GEAR WHICH IS THE MOST
APPROPRIATE TO THE DRIVING CONDITIONS AT THAT TIME, AND CONTROLS THE ENGINE TORQUE DURING SHIFTING TO ACHIEVE
OPTIMUM SHIFT FEELING.
1. GEAR SHIFT OPERATION
WHEN DRIVING, THE ENGINE WARM UP CONDITION IS INPUT AS A SIGNAL TO TERMINAL (B)44 OF THE ECU FROM THE EFI WATER
TEMP. SENSOR AND THE VEHICLE SPEED SIGNAL FROM SPEED SENSOR NO.2 IS INPUT TO TERMINAL (B)23 OF THE ECU. AT THE
SAME TIME, THE THROTTLE VALVE OPENING SIGNAL FROM THE THROTTLE POSITION SENSOR (MAIN) IS INPUT TO TERMINAL
(B)43 OF THE ECU AS ENGINE RPM CONDITION (IDLING, HIGH LOAD AND ACCELERATION CONDITIONS) SIGNAL.
BASED ON THESE SIGNALS, THE ECU SELECTS THE BEST SHIFT POSITION FOR DRIVING C\
ONDITIONS AND SENDS CURRENT TO
THE ECT SOLENOIDS.
WHEN SHIFTING TO 1ST SPEED, THE CURRENT FLOWS FROM TERMINAL (B)10 OF THE ECU " TERMINAL 1 OF ECT SOLENOIDS "
GROUND AND CONTINUITY TO NO.1 SOLENOID CAUSES THE SHIFT (NO.2 SOLENOID DOES NOT HAVE CONTINUITY AT THIS TIME).
FOR 2ND SPEED, THE CURRENT FLOWS SIMULTANEOUSLY FROM TERMINAL (B)9 OF THE ECU " TERMINAL 2 OF ECT SOLENOIDS
" GROUND, AND FROM TERMINAL (B)10 OF THE ECU " TERMINAL 1 OF ECT SOLENOIDS " GROUND, AND CONTINUITY TO NO.1
AND NO.2 SOLENOIDS CAUSES THE SHIFT.
FOR 3RD SPEED, THERE IS NO CONTINUITY TO NO.1 SOLENOID, ONLY TO NO.2 SOLENOID, CAUSING THE SHIFT.
SHIFTING INTO THE 4TH SPEED (OVERDRIVE) OCCURS WHEN NO CURRENT FLOWS TO NO.1 AND NO.2 SOLENOIDS. THE NO.4
SOLENOID (FOR ACCUMULATOR BACK PRESSURE MODULATION) IS INSTALLED TO ADJUST THE BACK PRESSURE ON THE
ACCUMULATOR AND CONTROL THE HYDRAULIC PRESSURE DURING SHIFTING AND LOCK±UP IN \
ORDER TO PROVIDE SMOOTH
SHIFTING WITH LITTLE SHIFT SHOCK.
2. LOCK±UP OPERATION
WHEN THE ECT ECU DECIDES, BASED ON EACH SIGNAL, THAT THE LOCK±UP CONDITION HAS BEEN MET, THE CURRENT FLOWS
FROM " TERMINAL (B)8 OF THE ECU " TERMINAL 3 OF THE ECT SOLENOID " GROUND, CAUSING CONTINUITY TO THE LOCK±UP
SOLENOID AND CAUSING LOCK±UP OPERATION.
3. STOP LIGHT SW CIRCUIT
IF THE BRAKE PEDAL IS DEPRESSED (STOP LIGHT SW ON) WHEN DRIVING IN LOCK±UP CONDITION, A SIGNAL IS INPUT\
TO
TERMINAL (A)4 OF THE ECU. THE ECU OPERATES AND CUTS THE CURRENT TO THE SOLENOID TO RELEASE LOCK±UP.
4. OVERDRIVE CIRCUIT
*O/D MAIN SW ON
WHEN THE O/D MAIN SW IS TURNED ON (SW POINT IS OPEN), A SIGNAL IS INPU\
T TO TERMINAL (A)28 OF THE ECU AND THE ECT
CAUSES SHIFT TO OVERDRIVE WHEN THE CONDITIONS FOR OVERDRIVE ARE MET.
* O/D MAIN SW OFF
WHEN THE O/D MAIN SW IS TURNED OFF (SW POINT IS CLOSED), THE CURRENT FLOWI\
NG THROUGH THE O/D OFF INDICATOR
LIGHT FLOWS TO GROUND BY WAY OF THE O/D MAIN SW AND CAUSES THE O/D OFF INDICATOR LIGHT TO LIGHT UP. AT THE
SAME TIME, A SIGNAL IS INPUT TO TERMINAL (A)28 OF THE ECU AND THE ECT PREVENTS SHIFT INTO OVERDRIVE.
5. ECT PATTERN SELECT SW CIRCUIT
WHEN THE ECT PATTERN SELECT SW IS CHANGED FROM ªNORMALº TO ªPOWERº, THE CURRENT THROUGH THE GAUGE FUSE
FLOWS TO TERMINAL 4 OF ECT PATTERN SELECT SW " TERMINAL 3 " TERMINAL (B)4 OF A/T INDICATOR " TERMINAL (C)23 "
GROUND AND CAUSES THE INDICATOR LIGHT TO LIGHT UP. AT THE SAME TIME, THE CURRENT FLOWS TO TERMINAL (A)18 OF
THE ECU AND THE ECU PERFORMS SHIFT UP AND SHIFT DOWN AT A HIGHER VEHICLE SPEED RANGE COMPARED WITH
ªNORMALº POSITION.
6. KICK DOWN OPERATION
WHEN THE ACCELERATOR IS DEPRESSED FURTHER THAN THE FULL THROTTLE POSITION WHILE DRIVING, THE KICK DOWN SW
TURNS ON AND ITS SIGNAL IS INPUT TO TERMINAL (A)3 OF THE ECU. THEN, THE ECU CONTROLS THE CURRENT WHICH FLOWS
FROM TERMINALS (B)10 AND (B)9 OF THE ECU TO THE NO. 1 AND NO. 2 SOLENOIDS AND SHIFTS DOWN BY TURNING THE
SOLENOIDS ON AND OFF.
7. CRUISE CONTROL
WHEN CRUISE CONTROL OPERATION IS SELECTED A SIGNAL IS INPUT TO TERMINAL (A)12 OF THE ECU FROM CRUISE CONTROL
ECU. AS A RESULT, THE ECU OPERATES AND CONTROLS OVERDRIVE, LOCK±UP AND SO ON FOR SMOOTH DRIVING.
SYSTEM OUTLINE
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131
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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