Lexus ES300 (1997 year). Manual - part 617

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IC REGULATOR

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GENERATOR

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FL MAIN
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IGNITION SW

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64

CHARGING

*  2 : CANADA

*   1  :  USA

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(HINT : SEE PAGE 7)

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(HINT : SEE PAGE 7)

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65

G 2  B

 GENERATOR

B 3–GROUND : 13.9–15.1 VOLTS WITH THE ENGINE RUNNING AT 2000 RPM AND 25

C (77

F)

13.5–14.3 VOLTS WITH THE ENGINE RUNNING AT 2000 RPM AND 115

C (239

F)

B 2–GROUND : 0–4 VOLTS WITH THE IGNITION SW AT ON POSITION AND ENGINE NOT RUNNING

SERVICE HINTS

: PARTS LOCATION

CODE

SEE PAGE

CODE

SEE PAGE

CODE

SEE PAGE

C 7

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: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR

CODE

SEE PAGE

JUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)

1B

1J

24

COWL WIRE AND INSTRUMENT PANEL J/B (LOWER FINISH PANEL)

1K

24

(

)

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INSTRUMENT PANEL WIRE AND INSTRUMENT PANEL J/B (LOWER FINISH PANEL)

2A

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ENGINE ROOM MAIN WIRE AND ENGINE ROOM J/B (ENGINE COMPARTMENT LEFT)

2C

20

ENGINE ROOM MAIN WIRE AND ENGINE ROOM J/B (ENGINE COMPARTMENT LEFT)

2L

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COWL WIRE AND ENGINE ROOM J/B (ENGINE COMPARTMENT LEFT)

: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS

CODE

SEE PAGE

JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)

EB2

34

COWL WIRE AND ENGINE ROOM MAIN WIRE (UNDER THE ENGINE ROOM J/B)

IG2

36

INSTRUMENT PANEL WIRE AND COWL WIRE (RIGHT SIDE OF INSTRUMENT PANEL J/B)

IN2

38

ENGINE ROOM MAIN WIRE AND COWL WIRE (RIGHT KICK PANEL)

: SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

E 2

34

COWL WIRE

66

ENGINE CONTROL

THIS SYSTEM UTILIZES AN ENGINE CONTROL MODULE AND MAINTAINS OVERALL CONTROL OF THE ENGINE,
TRANSMISSION AND SO ON. AN OUTLINE OF THE ENGINE CONTROL IS EXPLAINED HERE.

1. INPUT SIGNALS

( 1) ENGINE COOLANT TEMP. SIGNAL CIRCUIT

THE ENGINE COOLANT TEMP. SENSOR DETECTS THE ENGINE COOLANT TEMP. AND HAS A BUILT–IN 
THERMISTOR WITH A RESISTANCE WHICH VARIES ACCORDING TO THE WATER TEMP. IS INPUT INTO 
TERMINAL THW OF THE ENGINE CONTROL MODULE AS A CONTROL SIGNAL.

( 2) INTAKE AIR TEMP. SIGNAL CIRCUIT

THE INTAKE AIR TEMP. SENSOR IS INSTALLED IN THE MASS AIR FLOW METER AND DETECTS THE INTAKE AIR 
TEMP., WHICH IS INPUT AS A CONTROL SIGNAL INTO TERMINAL THA OF THE ENGINE CONTROL MODULE.

( 3) OXYGEN SENSOR SIGNAL SYSTEM

THE OXYGEN DENSITY IN THE EXHAUST GASES IS DETECTED AND INPUT AS A CONTROL SIGNAL INTO 
TERMINALS OXL1, OXR1 AND OXS OF THE ENGINE CONTROL MODULE TO MAINTAIN STABLE DETECTION 
PERFORMANCE BY THE HEATED OXYGEN SENSOR, A HEATER IS USED FOR WARMING THE SENSOR.  THE 
HEATER IS ALSO CONTROLLED BY THE ENGINE CONTROL MODULE (HTL, HTR AND HTS).

( 4) RPM SIGNAL SYSTEM

CAMSHAFT POSITION AND CRANKSHAFT POSITION ARE DETECTED BY THE CAMSHAFT POSITION SENSOR AND 
CRANKSHAFT POSITION SENSOR. THE CAMSHAFT POSITION IS INPUT AS A CONTROL SIGNAL TO TERMINAL 
G22+ OF THE ENGINE CONTROL MODULE, AND THE ENGINE RPM IS INPUT INTO 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 ENGINE CONTROL MODULE.

( 6) VEHICLE SPEED SIGNAL SYSTEM

THE VEHICLE SPEED SENSOR, INSTALLED INSIDE THE TRANSMISSION, DETECTS THE VEHICLE SPEED AND 
INPUTS A CONTROL SIGNAL INTO TERMINAL SPD OF THE ENGINE CONTROL MODULE.

( 7) PARK/NEUTRAL POSITION SW SIGNAL SYSTEM

THE PARK/NEUTRAL POSITION SW DETECTS WHETHER THE SHIFT POSITION IS IN NEUTRAL, PARKING OR 
NOT, AND INPUTS A CONTROL SIGNAL INTO TERMINAL STA OF THE ENGINE CONTROL MODULE

( 8) A/C SW SIGNAL SYSTEM

THE A/C CONTROL ASSEMBLY INPUTS THE A/C OPERATIONS INTO TERMINAL A/C OF THE ENGINE CONTROL 
MODULE AS A CONTROL SIGNAL.

( 9) BATTERY SIGNAL CIRCUIT

VOLTAGE IS CONSTANTLY APPLIED TO TERMINAL BATT OF THE ENGINE CONTROL MODULE. WHEN THE 
IGNITION SW IS TURNED ON, VOLTAGE FOR THE ENGINE CONTROL MODULE OPERATION IS APPLIED TO 
TERMINAL +B OF THE ENGINE CONTROL MODULE VIA THE EFI RELAY.

(10) INTAKE AIR VOLUME SIGNAL CIRCUIT

INTAKE AIR VOLUME IS DETECTED BY THE MASS AIR FLOW METER AND A SIGNAL IS INPUT INTO TERMINAL 
VG OF THE ENGINE CONTROL MODULE AS A CONTROL SIGNAL.

(11) NSW 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 NSW OF THE ENGINE CONTROL MODULE 
AS A CONTROL SIGNAL.

(12) ENGINE KNOCK SIGNAL CIRCUIT

ENGINE KNOCKING IS DETECTED BY THE KNOCK SENSOR 1 AND 2, THEN THE SIGNALS ARE INPUT INTO 
TERMINALS KNKR AND KNKL OF THE ENGINE CONTROL MODULE AS A CONTROL SIGNAL.

SYSTEM OUTLINE

67

2. CONTROL SYSTEM

SFI (SEQUENTIAL MULTIPORT FUEL INJECTION) SYSTEM
THE SFI SYSTEM MONITORS THE ENGINE CONDITION THROUGH THE SIGNALS, WHICH ARE INPUT FROM EACH 
SENSOR (INPUT SIGNALS (1) TO (12)). THE BEST FUEL INJECTION VOLUME IS DECIDED BASED ON THIS DATA

AND 
THE PROGRAM MEMORIZED BY THE ENGINE CONTROL MODULE, AND THE CONTROL SIGNAL IS OUTPUT TO 

TERMINALS #10, #20, #30, #40, #50, AND #60 OF THE ENGINE CONTROL MODULE TO OPERATE THE INJECTOR 
(INJECT THE FUEL). THE SFI SYSTEM PRODUCES CONTROL OF FUEL INJECTION OPERATION BY THE ENGINE 
CONTROL MODULE IN RESPONSE TO THE DRIVING CONDITIONS.

ESA (ELECTRONIC SPARK ADVANCE) SYSTEM
THE ESA SYSTEM MONITORS THE ENGINE CONDITION THROUGH THE SIGNALS, WHICH ARE INPUT TO THE 
ENGINE CONTROL MODULE FROM EACH SENSOR (INPUT SIGNALS FROM 1, 3, 4, 12). THE BEST IGNITION TIMING
IS DECIDED ACCORDING TO THIS DATA AND THE MEMORIZED DATA IN THE ENGINE CONTROL MODULE AND 
THE CONTROL SIGNAL IS OUTPUT TO TERMINALS IGT1, IGT2 AND IGT3. THIS SIGNAL CONTROLS THE IGNITER 
TO PROVIDE THE BEST IGNITION TIMING FOR THE DRIVING CONDITIONS.

HEATED OXYGEN SENSOR HEATER CONTROL SYSTEM
THE HEATED 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 HEATED OXYGEN SENSOR TO 
IMPROVE DETECTION PERFORMANCE OF THE SENSOR. THE ENGINE CONTROL MODULE EVALUATES THE 
SIGNALS FROM EACH SENSOR (INPUT SIGNALS FROM 1, 4, 9, 10), CURRENT IS OUTPUT TO TERMINALS HTL, 
HTR AND HTS, CONTROLLING THE HEATER.

IDLE AIR CONTROL SYSTEM
THE IDLE AIR CONTROL SYSTEM (ROTARY SOLENOID TYPE) INCREASES THE RPM AND PROVIDES IDLE 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 ENGINE CONTROL MODULE EVALUATES THE SIGNALS FROM EACH SENSOR (INPUT 
SIGNALS FROM 1, 4, 5, 8, 9), CURRENT IS OUTPUT TO TERMINALS RSO AND RSC TO CONTROL IDLE AIR CONTROL 
VALVE.

EGR CONTROL SYSTEM
THE EGR CONTROL SYSTEM DETECTS THE SIGNAL FROM EACH SENSOR (INPUT SIGNALS FROM 1, 4, 9, 10),  
AND OUTPUTS CURRENT TO TERMINAL EGR TO CONTROL THE VSV (EGR).
THE EGR VALVE POSITION SENSOR IS MOUNTED ON THE EGR VALVE. THIS SENSOR CONVERTS THE EGR VALVE 
OPENING HEIGHT INTO A VOLTAGE AND SENDS IT TO THE ENGINE CONTROL MODULE AS THE EGR VALVE 
POSITION SIGNAL.

ACIS (ACOUSTIC CONTROL INDUCTION SYSTEM)
ACIS INCLUDES A VALVE IN THE BULKHEAD SEPARATING THE SURGE TANK INTO TWO PARTS. THIS VALVE 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 ENGINE CONTROL MODULE JUDGES THE ENGINE SPEED BY THE SIGNALS ((4),  (5)) FROM EACH SENSOR 
AND OUTPUTS SIGNALS TO THE TERMINAL ACIS TO CONTROL THE VSV (INTAKE AIR CONTROL).

3. DIAGNOSIS SYSTEM

WITH THE DIAGNOSIS SYSTEM, WHEN THERE IS A MALFUNCTION IN THE ENGINE CONTROL MODULE SIGNAL
SYSTEM, THE MALFUNCTIONING SYSTEM IS RECORDED IN THE MEMORY.

4. FAIL–SAFE SYSTEM

WHEN A MALFUNCTION OCCURS IN ANY SYSTEMS, 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 ENGINE CONTROL
MODULE MEMORY OR ELSE STOPS THE ENGINE.