Lexus ES300 (1997 year). Manual - part 650

194

ABS AND TRACTION CONTROL

(ABS)
ABS IS A BRAKE SYSTEM DESIGNED FOR THE PURPOSE TO IMPROVE THE OPERATING ABILITY SECURING THE STABILITY OF
THE VEHICLE BY PREVENTING THE LOOKING–UP OF THE VEHICLE CONTROLLING THE WHEEL CYLINDER PRESSURE OF ALL
THE FOUR WHEELS AT THE TIME OF SUDDEN BRAKING.

1. INPUT SIGNALS

(1)

SPEED SENSOR SIGNAL
THE 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 BRAKE PEDAL IS DEPRESSED.

2. SYSTEM OPERATION

WHEN THE WHEELS ARE TO BE LOCKED–UP, THE SOLENOID INSIDE THE ACTUATOR WILL BE CONTROLLED BY THE SIGNAL
FROM THE ABS AND TRACTION ECU AND THE BRAKE FLUID IN THE WHEEL CYLINDER WILL FLOW THROUGH THE RESERVOIR
AND REDUCE THE HYDRAULIC PRESSURE.
WHILE THE ABS IS IN OPERATION, AS THE ABS AND TRACTION ECU IS ALWAYS OUTPUTTING THE OPERATION SIGNAL TO THE
PUMP INSIDE THE ACTUATOR, BRAKE FLUID STORED INSIDE THE RESERVOIR WILL BE SUCTIONED UP BY THE PUMP INSIDE THE
ACTUATOR AND RETURNED TO THE MASTER CYLINDER.
WHEN THE HYDRAULIC PRESSURE OF THE WHEEL CYLINDER IS DECOMPRESSED OR INCREASED UNTIL THE NECESSARY
HYDRAULIC PRESSURE, THE SOLENOID INSIDE THE ACTUATOR IS CONTROLLED BY THE CONTROL SIGNAL FROM THE ABS AND
TRACTION ECU AND AS A RESULT, HYDRAULIC PRESSURE OF THE WHEEL CYLINDER WILL BE CLOSED AT BOTH ROUTES OF
THE MASTER CYLINDER AND RESERVOIR SIDES AND THE HYDRAULIC PRESSURE OF THE WHEEL CYLINDER WILL BECOME TO
BE IN THE HOLDING CONDITION.
IF THE INCREASE OF HYDRAULIC PRESSURE VOLUME OF THE WHEEL CYLINDER BECOMES NECESSARY, WITH THE CONTROL
SIGNAL FROM THE ABS AND TRACTION ECU, THE SOLENOID INSIDE THE ACTUATOR WILL BE CONTROLLED AND BECOME THE
SAME CONDITION AS USUAL AND THE BRAKE FLUID OF THE MASTER CYLINDER WILL BE SENT TO THE WHEEL CYLINDER AND
WILL INCREASE THE HYDRAULIC PRESSURE OF THE WHEEL CYLINDER. AT THIS TIME, IN THE CASE THAT THE BRAKE FLUID
STAYS LEFT IN THE RESERVOIR, IT WILL BE SUCTIONED UP BY THE PUMP INSIDE THE ACTUATOR AND WILL BE SENT TO THE
WHEEL CYLINDER.
ALSO, INCREASING SPEED OF THE HYDRAULIC PRESSURE IS CONTROLLED BY OUTPUTTING THE INCREASING AND THE SAID
HOLDING ONE AFTER ANOTHER.
(TRACTION CONTROL)
TRACTION CONTROL SYSTEM IS DESIGNED TO PERFORM THE ENGINE OUTPUT CONTROL BY THE FUEL CUT AND HYDRAULIC
PRESSURE CONTROL OF DRIVING WHEEL BRAKE AND CONTROL THE SPINNING OF THE DRIVING WHEELS. BY DOING THIS, IT
IMPROVES STARTING ACCELERATION AND OPERATING ABILITY OF THE VEHICLE SECURING THE DRIVING ABILITY IN
ACCORDANCE WITH THE ROAD SURFACE CONDITION.

3. TRACTION CONTROL OPERATION

ESTIMATING THE VEHICLE SPEED FROM THE REAR WHEEL SPEED, COMPARING IT WITH THE FRONT, DRIVING WHEEL SPEED
AND JUDGING THE GRIP CONDITION OF THE DRIVING WHEELS. FROM THE ESTIMATED VEHICLE SPEED, TARGET SPEED OF THE
DRIVING SPEED WILL BE SET. WHEN THE FRONT, DRIVING WHEEL SPEED EXCEEDS THE CONTROL STARTING SPEED, IT
JUDGES THAT THE TIRE SLIP IS OCCURRED AND PERFORMS THE FUEL CUT CYLINDER NUMBER CONTROL AND BRAKE
CONTROL AND THEN ADJUST TO MAKE THE FRONT WHEEL SPEED BECOME THE TRACTION CONTROL TARGET SPEED.
CONTROLLING OF THE TRACTION CONTROL WILL BE COMPLETED WHEN THE VEHICLE MOVE ONTO THE ROAD WHERE THE
DRIVING WHEELS WILL NOT HAVE A TIRE SLIP OR WHEN THE DRIVER DECELERATE.

SYSTEM OUTLINE

A

B

C

195

A19      , A20      ,A21       ABS AND TRACTION ECU

IG1 – GND : 10–14 VOLTS WITH IGNITION SW AT ON POSITION

R+ – SR : 9–14 VOLTS WITH IGNITION SW AT ON POSITION AND ABS WARNING LIGHT OFF

R+ – MR : 0–1 VOLTS WITH IGNITION SW AT ON POSITION

WA – GND : 0–2 VOLTS WITH IGNITION SW AT ON POSITION AND ABS WARNING LIGHT ON

: 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND ABS WARNING LIGHT OFF

STP – GND : 0–1.5 VOLTS WITH STOP LIGHT SW OFF

: 8–14 VOLTS WITH STOP LIGHT SW ON

D/G – GND : 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND ABS WARNING LIGHT ON

MT – GND : 0–1.5 VOLTS WITH IGNITION SW AT ON POSITION

NEO – GND : PULES GENERATION WITH IDLING

IND – GND : 0–2 VOLTS WITH IGNITION SW AT ON POSITION AND SLIP INDICATOR LIGHT ON

: 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND SLIP INDICATOR LIGHT OFF

WT – GND : 0–2 VOLTS WITH IGNITION SW AT ON POSITION AND TRAC OFF INDICATOR LIGHT ON

; 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND TRAC OFF INDICATOR LIGHT OFF

CSW – GND : 0–2 VOLTS WITH IGNITION SW AT ON POSITION AND TRAC OFF SW PUSHED

: 8–14 VOLTS WITH IGNITION SW AT ON POSITION AND TRAC OFF SW RELEASED

TC, TS – GND : 8–14 VOLTS WITH IGNITION SW AT ON POSITION

TRC+, TRC– – GND :

PULES GENERATION WITH TRACTION CONTROL ACTIVE

EFI+, ERI– – GND : PULES GENERATION WITH IGNITION SW AT ON POSITION

SRLH, SRLH, AST – GND : 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND WARNING LIGHT OFF

SFLH, SRRR, SRRH – GND : 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND WARNING LIGHT OFF
SFRR, SFRH, SFLR – GND : 10–14 VOLTS WITH IGNITION SW AT ON POSITION AND WARNING LIGHT OFF
SRC1, SRC2, SMC1, SMC2 – GND  :   10–14 VOLTS WITH IGNITION SW AT ON POSITION AND TRAC OFF INDICATOR LIGHT OFF

S10 STOP LIGHT SW

2–1 : CLOSED WITH BRAKE PEDAL DEPRESSED

A 9, A10, A34, A35 ABS SPEED SENSOR FRONT LH, RH, REAR LH, RH

1–2 : 1.5–1.7 K

Ω

 (20

°

C 68

°

F)

: PARTS LOCATION

CODE

SEE PAGE

CODE

SEE PAGE

CODE

SEE PAGE

A 7

A

26

C 8

B

28

J 9

B

29

A 8

B

26

C10

D

28

J15

29

A 9

26

D 1

26

J24

29

A10

26

D 3

28

J27

29

A19

A

28

E 7

A

28

J28

A

29

A20

B

28

E 9

C

28

J29

B

29

A21

C

28

J 1

29

J30

29

A24

28

J 3

29

S10

29

A33

30

J 4

29

T 2

27

A34

30

J 8

A

29

T 5

29

: RELAY BLOCKS

CODE

SEE PAGE

RELAY BLOCKS (RELAY BLOCK LOCATION)

3

23

ENGINE ROOM NO.3 R/B (RADIATOR UPPER SUPPORT RH)

,,,

,,,

,,,

: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR

CODE

SEE PAGE

JUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)

1C

24

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

1D

24

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

1J

24

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

1R

24

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

SERVICE HINTS

196

ABS AND TRACTION CONTROL

: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS

CODE

SEE PAGE

JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)

ID1

36

FLOOR WIRE AND COWL (LEFT KICK PANEL)

IJ1

38

INSTRUMENT PANEL WIRE AND COWL WIRE (UNDER THE GLOVE BOX)

IK3

38

ENGINE WIRE AND COWL WIRE (UNDER THE GLOVE BOX)

IH1

IM2

38

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

IM3

(

)

IN1

38

FLOOR NO. 2 WIRE AND COWL WIRE (RIGHT KICK PANEL)

: GROUND POINTS

CODE

SEE PAGE

GROUND POINTS LOCATION

EA

34

RIGHT RADIATOR SIDE SUPPORT

EB

34

RIGHT RADIATOR SIDE SUPPORT

ED

34

SURGE TANK RH

II

36

INSTRUMENT PANEL BRACE LH

: SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

E 1

34

ENGINE ROOM MAIN WIRE

1

2

3

4

5

1

2

1

2

1

X X 4 5 6 X X 9 10 11 12 13

14 15

X 17 18 19 X X 22 23

24 25 26

1 2 3 4 5 6 X 8

9 10 11 12 13 14 15 16

1

2

X

4

5

6

7

8

9 10 X 12

X

X

18

20

X X X

1

2

1

2

4

A

GRAY

A 7

B

BLACK

A 8

A

A19

B

A20

C

A21

B

C 8

A 9

GRAY

A10 GRAY

A33 GRAY

A24 GRAY

A34 GRAY

1

2

3

4

5

6

7

8

9 10

11 12

X

X

197

7

6

3

X X

X

X

X

X

X 11

X X

X

16 X

X

X

X

23

22

X

X

X

4

X

X

X

X

X

X

X

X

14

X

17

X

X

1

X

7

X

22

X

19 X X

X

X

25 26 27 28

B B

B B

A A A A A

D D D

A A A A A A

A A A A A A

A

A

A

A

A

A

A A A A A

A A

X X

C C

X X

C C C

F F

1

2

1 2 3

1 X X

4

D BROWN

C10

C

E 9

A

E 7

A GRAY

J 8

B GRAY

J 9

A

J28

B

J29

J30

S10 BLUE

T 2 BLACK

T 5 BLACK

D 1 BLACK

D 3 DARK GRAY

J 4 BLACK

J 3

J 1 GRAY

J15

J27

A A

A A

A A A A A A A

3

3

B

B

B

C C C

B B B

J24

F F

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