Lexus ES300 (2002 year). Service manual - part 19

176

ABS

10A
ECU–IG

2G

21

From Power Source System (See Page 56)

1G

ID1

13

2

1

ID1

3

IF4

8

2

1

IF4

9

IO5

14

IO5

15

1

2

1

2

2G

11

2G

23

15A
STOP

2G

13

IF4

21

3B

52

3B

42

2G

7

2G

19

L

L

Y–

R

W

G–

W

G–

W

W

P–

B

LG

–

B

P–

B

R

G

P

L

R

G

P

L

P

L

B

W

Y

BR

R–

W

R–

W

25

23

1

10

14

16

14

13

11

12

33

34

30

31

8

9

18

Data Link Connector 3

D 2

Skid Control ECU with Actuator

S 1

ABS Speed Sensor
Rear LH

A36

ABS Speed Sensor
Rear RH

A37

ABS Speed Sensor
Front RH

A 7

ABS Speed Sensor
Front LH

A 6

W

3B

51

3B

41

TS

TC

1

2

1

2

40A
ABS
NO. 3

2

40A
ABS
NO. 2

1

1

1E

7

IF7

LG

–B

15

SIL

W

7

18 2G

3 2L

2L

4

2P

4

W

W

S

top

 Li

g

h

t S

W

S1

3

P

a

rk

ing B

rak

e S

W

P 5

H

e

a

d

lig

h

t B

eam

 Lev

el

Co

n

tr

o

l E

C

U

H1

4

IF8

3

20

G

R

–R

G

R

–R

26

SPDR

(*1

)

(*1

)

7

5

FL–

FL+

FR–

FR+

RL+

RL–

RR+

RR–

PKB

+BM

+BS

IG1

STP

TS

D/G

TC

FRO

177

10A
GAUGE2

2B

6

A

6

B

17

B

10

IF7

12

IF4

10

IF7

13

EA

EB

From Power Source System (See Page 56)

R–

L

R–

B

R–

Y

L–

W

R–

B

L–

O

L–

W

W

R–

Y

W–

B

W–

B

W–

B

W–

B

13

32

2

24

Combination Meter

C 7(A), C 8(B)

*  1 : w/ Headlight Beam Level Control System

3B

65

3B

55

3B

76

3B

66

3A

57

3A

87

40 A

W

E 1

E 1

P

N

10A
GAUGE1

2M

1

W

IL2

3

W

A

37

W

A

36

110 3A

3A

90

99 3B

3B

89

A

32

IF4

22

L–

O

W

26

A

/T

 I

ndi

c

a

to

r

L

ight

 S

W

A 4

R

G–

W

R–

L

R

G–

W

5

1

3

IL1

19

IL1

18

W

W

L–W

5

W

A

21

BR

W

54 3A

3A

64

BR

ID

W–B

Power

ABS

BR

AKE

Skid Control ECU
with Actuator

S 1

Micro Computer

GND1

GND2

PN

WA

SP1

BRL

178

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
directional stability and steerability during panic braking.

1. Input Signals

(1) Speed sensor signal

The speed of the wheels is detected and input to TERMINALS 9, 11, 31 and 33 of the skid control ECU with actuator.

(2) Stop light SW signal

A signal is input to TERMINAL 10 of the skid control ECU with actuator when the brake pedal is depressed.

2. System Operation

During sudden braking the skid control ECU with actuator has signals input from each sensor, which controls the current 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 skid control ECU with actuator judges that the hydraulic pressure acting on the wheel cylinder is insufficient, the current
on the solenoid is controlled and the hydraulic pressure is increased. Holding of the hydraulic pressure is also controlled by
the skid control ECU with actuator, by the same method as above. Pressure reduction, holding and increase are repeated to
maintain vehicle stability and to improve steerability during sudden braking.

A6, A7  ABS Speed Sensor Front LH, RH

2–1 : Approx. 2.3 k

Ω

A36, A37  ABS Speed Sensor Rear LH, RH

2–1 : Approx. 1.6 k

Ω

S1  Skid Control ECU with Actuator

2, 24–Ground : Always continuity

25–Ground : Approx. 12 volts with the ignition SW at ON position
10–Ground : Approx. 12 volts with the brake pedal depressed

1, 23–Ground : Always approx. 12 volts

  :  Parts Location

Code

See Page

Code

See Page

Code

See Page

A4

36

A37

40

H14

39

A6

36

C7

A

38

P5

39

A7

36

C8

B

38

S1

37

A36

40

D2

38

S13

39

: Junction Block and Wire Harness Connector

Code

See Page

Junction Block and Wire Harness (Connector Location)

1E

25

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

1G

25

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

2B

28

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

2G

28

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

2L

2M

29

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

2P

(

)

3A

35 (w/o VSC)

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

3B

35 (w/o VSC)

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

System Outline

Service Hints

179

: Connector Joining Wire Harness and Wire Harness

Code

See Page

Joining Wire Harness and Wire Harness (Connector Location)

ID1

46

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

IF4

IF7

46

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

IF8

g

( g

g

)

IL1

48

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

IL2

48

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

IO5

48

Instrument Panel Wire and Floor No.2 Wire (Right Kick Panel)

: Ground Points

Code

See Page

Ground Points Location

EA

44

Right Fender

EB

44

Right Fender

ID

46

Instrument Panel Brace RH

: Splice Points

Code

See Page

Wire Harness with Splice Points

Code

See Page

Wire Harness with Splice Points

E1

44

Engine Room Main Wire