Lexus ES300 (2002 year). Manual — part 50

74

Engine Control

2. Control System

∗

SFI system
The SFI system monitors the engine condition through the signals, which are input from each sensor to engine control
module. 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 system
The ESA system monitors the engine condition through the signals, which are input to the engine control module from
each sensor. 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, IGT3, IGT4, IGT5 and IGT6. 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, current is output to TERMINALS HT1B and HT2B,
controlling the heater.

∗

Air fuel ratio sensor heater control system
The air fuel ratio sensor heater control system turns the heater on when the intake air volume is low (Temp. of exhaust
emission is low), and warms up the air fuel ratio sensor to improve detection performance of the sensor.
The engine control module evaluates the signals from each sensor, current is output to TERMINALS HAFR and HAFL,
controlling the heater.

∗

ACIS
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 from each sensor and outputs current to the
TERMINAL ACIS to control the VSV (ACIS No.1).

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.

75

E3 Engine Coolant Temp. Sensor

1–2 : Approx. 15.04 k

Ω

(–20

C, –4

F)

Approx. 5.74 k

Ω

(0

C, 32

F)

Approx. 2.45 k

Ω

(20

C, 68

F)

Approx. 1.15 k

Ω

(40

C, 104

F)

Approx. 0.584 k

Ω

(60

C, 140

F)

Approx. 0.318 k

Ω

(80

C, 176

F)

E6 (A), E7 (B), E8 (C), E9 (D), E10 (E) Engine Control Module

Voltage at engine control module wiring connector

BATT–E1 : Always 9.0–14.0 volts

+B–E1 : 9.0–14.0 volts (Ignition SW at ON position)

VC–E2 : Always 4.5–5.5 volts (Ignition SW at ON position)

VTA1–E2 : 0.3–0.8 volts (Ignition SW on and throttle valve fully closed)

: 3.2–4.9 volts (Ignition SW on and throttle valve fully open)

VG–E2G : 1.1–1.5 volts (Engine idling and A/C SW OFF position)

THA–E2 : 0.5–3.4 volts (Engine idling and intake air temp. 20

°

C, 68

°

F)

THW–E2 : 0.2–1.0 volts (Engine idling and engine coolant temp. 80

°

C, 176

°

F)

IGF–E1 : 4.5–5.5 volts (Ignition SW at ON position)

Pulse generation (Engine idling)

VV1+–NE– : Pulse generation (Engine idling)

NE+–NE– : Pulse generation (Engine idling)

NSW–E1 : 9.0–14.0 volts (Ignition SW on and other shift position in P or N position)

Below 3.0 volts (Ignition SW on and shift position in P or N position)

SPD–E1 : Pulse generation (Ignition SW on and rotate driving wheel slowly)

W–E1 : Below 3.0 volts

ACIS–E01 : 9.0–14.0 volts (Ignition SW at ON position)

STA–E1 : 6.0 volts or more (Engine cranking)
ELS–E1 : 7.5–14.0 volts (Taillight SW at ON position)

0–1.5 volts (Taillight SW at OFF position)

ELS2–E1 : 7.5–14.0 volts (Defogger SW at ON position)

0–1.5 volts (Defogger SW at OFF position)

FC–E1 : 9.0–14.0 volts (Ignition SW at ON position)

0–3.0 volts (Engine idling)

EVP1–E01 : 9.0–14.0 volts (Ignition SW at ON position)

CF–E1 : 9.0–14.0 volts (Electric cooling fan is operating on high speed)

0–2.0 volts (Electric cooling fan is operating on low speed or off)

TACH–E1 : Pulse generation (Engine idling)

TBP–E1 : 9.0–14.0 volts (Ignition SW on and disconnect the vacuum hose from the vapor pressure sensor)

PTNK–E1 : 3.0–3.6 volts (Ignition SW at ON position)

1.3–2.1 volts (Ignition SW on and apply vacuum 2.0 kpa (15.0 mmHg, 0.6 in.Hg)

STP–E1 : 7.5–14.0 volts (Ignition SW on and brake pedal depressed)

Below 1.5 volts (Ignition SW on and brake pedal released)

SIL–E1 : Pulse generation (During transmission)

KNKL, KNKR–E1 : Pulse generation (Engine idling)

HT1B, HT2B–E03 : 9.0–14.0 volts (Ignition SW at ON position)

0–3.0 volts (Engine idling)

OX1B, OX2B–E1 : Pulse generation (Maintain engine speed at 2500 rpm for two minutes after warning up)

IGT1, IGT2, IGT3, IGT4, IGT5, IGT6–E1 : Pulse generation (Engine idling)

#10, #20, #30, #40, #50, #60–E01 : 9.0–14.0 volts (Ignition SW at ON position)

Pulse generation (Engine idling)

I7, I8, I9, I10, I11, I12 Injector

2–1 : Approx. 13.8

Ω

C/OPN Relay

3–5 : Closed with starter running

EFI Relay

3–5 : Closed with ignition SW at ON or ST position

Service Hints

76

Engine Control

: Parts Location

Code

See Page

Code

See Page

Code

See Page

A4

36

I2

37

S6

B

39

A10

36

I3

37

S7

C

39

A11

36

I4

37

S13

39

A14

38

I5

37

T2

37

A25

38

I6

37

T3

37

C2

36

I7

37

V1

37

C7

A

38

I8

37

V2

37

C8

B

38

I9

37

V3

37

D2

38

I10

37

V4

37

E3

36

I11

37

V5

37

E6

A

38

I12

37

V6

37

E7

B

38

I13

39

V7

37

E8

C

38

I14

39

V8

37

E9

D

38

J11

39

V9

37

E10

E

38

J12

40

V10

37

F15

40

K2

37

V14

41

H9

36

K3

37

V17

41

H10

36

M1

37

I1

37

P3

37

: Relay Blocks

Code

See Page

Relay Blocks (Relay Block Location)

1

22

Engine Room R/B (Engine Compartment Left)

: Junction Block and Wire Harness Connector

Code

See Page

Junction Block and Wire Harness (Connector Location)

1A

1B

1C

1D

25

Engine Room Main Wire and Engine Room J/B (Engine Compartment Left)

1E

g

g

(

g

)

1H

1J

1K

25

Engine Wire and Engine Room J/B (Engine Compartment Left)

1L

25

Engine Wire and Engine Room J/B (Engine Compartment Left)

2A

28

Instrument Panel Wire and Driver Side J/B (Lower Finish Panel)

2E

28

Engine Room Main Wire and Driver Side J/B (Lower Finish Panel)

2G

28

Engine Room Main Wire and Driver Side J/B (Lower Finish Panel)

2K

28

Floor No.1 Wire and Driver Side J/B (Lower Finish Panel)

2L

2M

29

Instrument Panel Wire and Driver Side J/B (Lower Finish Panel)

2O

29

Instrument Panel Wire and Driver Side J/B (Lower Finish Panel)

2R

3A

34 (w/ VSC)

3A

35 (w/o VSC)

Instrument Panel Wire and Passenger Side J/B (Instrument Panel Brace RH)

3B

34 (w/ VSC)

Instrument Panel Wire and Passenger Side J/B (Instrument Panel Brace RH)

3B

35 (w/o VSC)

77

: Connector Joining Wire Harness and Wire Harness

Code

See Page

Joining Wire Harness and Wire Harness (Connector Location)

EB1

44

Engine Wire and Sensor Wire (Left Bank of the Cylinder Head)

IA3

46

Instrument Panel Wire and Floor No.1 Wire (Left Kick Panel)

ID1

46

Engine Room Main Wire and Floor No.1 Wire (Left Side of Driver Side J/B)

IF3

IF4

IF5

46

Engine Room Main Wire and Instrument Panel Wire (Right Side of Steering Column Tube)

IF6

g

( g

g

)

IF7

IK1

48

Instrument Panel Wire and Instrument Panel Wire (Instrument Panel Reinforcement RH)

IL1

48

Engine Wire and Instrument Panel Wire (Behind the Glove Box)

IL2

48

Engine Wire and Instrument Panel Wire (Behind the Glove Box)

: Ground Points

Code

See Page

Ground Points Location

EC

44

Left Fender

ED

44

Left Fender

EE

44

Left Side of Cylinder Head

EF

44

Intake Side of Cylinder Block

IA

46

Instrument Panel Reinforcement LH

ID

46

Instrument Panel Brace RH

BC

50

Front Side of Rear Quarter Wheel House LH

: Splice Points

Code

See Page

Wire Harness with Splice Points

Code

See Page

Wire Harness with Splice Points

E2

44

Engine Wire

I6

E3

44

Engine Wire

I7

48

Engine Wire

I2

48

Engine Room Main Wire

I8

g