Lexus ES300 (2002 year). Manual - part 303

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DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

05-333

486

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

CHECK BRAKE FLUID LEVEL IN RESERVOIR

(a)

Check the amount of brake fluid in the reservoir.

NG

CHECK AND REPAIR BRAKE FLUID LEAKAGE
AND ADD FLUID

OK

2

INSPECT BRAKE MASTER CYLINDER RESERVOIR  SUB-ASSY(FULUID  LEVEL
WARNING SWITCH)

(a)

Check that continuity exists between the terminals.
OK:
Float up: About 2 k

Ω

Float down: Continuity

NG

REPLACE BRAKE MASTER CYLINDER
RESERVOIR SUB-ASSY

OK

3

CHECK FOR OPEN CIRCUIT IN ALL HARNESS AND COMPONENTS CONNECTED
TO BRAKE WARNING LIGHT

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE SKID CONTROL ECU ASSY

F41982

Skid Control ECU

ENG+

S7

9

ECM

ENG-

S7

18

TRC+

S7

11

TRC-

S7

20

ENG+

ENG-

TRC+

TRC-

E6

24

E6

30

E6

25

E6

31

IF4

IF4

IF4

IF4

7

9

10

8

B

W

G

L

B

W

G

L

05-334

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DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

487

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1203/53 ECM COMMUNICATION CIRCUIT

MALFUNCTION

CIRCUIT DESCRIPTION

The circuit is used to send TRAC & VSC control information from the skid control ECU to the ECM (TRC+,
TRC-),  and engine control information from the ECM to the skid control ECU (ENG+, ENG-).

DTC No.

DTC Detecting Condition

Trouble Area

C1203 / 53

Either of the following 1., 2. or 3. continues for 5 sec.:

1. When ECU terminal IG1 voltage is 9.5 V or more, the

condition that the data is not transmitted to ECM contin-

ues for more than 5 sec.

2. When ECU terminal IG1 voltage is 9.5 V or more, engine

speed is 500 rpm or more and data receipt from ECM is

impossible.

3. The condition that data transmission and reception to/

from ECM become impossible once or more within 5

sec. repeatedly occurs 10 times.

TRC+ or TRC- circuit

ENG+ or ENG- circuit

ECM

WIRING DIAGRAM

052B0-03

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

05-335

488

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

CHECK HARNESS AND CONNECTOR(ENG+, ENG-, TRC+, TRC- OF ECM AND
SKID CONTROL ECU)

(a)

Check for open and short circuit in harness and connector between each of terminals ENG+, ENG-,
TRC+, TRC- of skid control ECU and the same one of the ECM (See page 

01-31

).

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE ECM AND SKID CONTROL ECU

F41043

Skid Control ECU

Y1
Yaw Rate Sensor

(Shielded)

16

YD

S6

G

10

YAW

S6

20

GYAW

S6

3

YSS

S6

W

B

6

1

5

YD

YAW2

GYAW

05-336

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DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

489

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1210/36 ZERO POINT CALIBRATION OF YAW RATE

SENSOR UNDONE

DTC

C1233/33 OPEN OR SHORT CIRCUIT IN YAW RATE

SENSOR CIRCUIT

DTC

C1234/34 MALFUNCTION IN YAW RATE SENSOR

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

C1210/36

1. After ECU was replaced, when the shift lever was

moved other than to P position within 15 sec. soon after

ECU terminal IG1 become ON for the first time.

2. When the yaw rate sensor zero point recorded in ECU is

deleted.

Yaw rate sensor

Yaw rate sensor circuit

P position switch circuit

C1233/33

Detection of any of conditions 1. through 4.:
1. When the ECU IG1 terminal voltage is 9.5 to 17.2 V, the

yaw rate sensor voltage is out of the range from 0.25 to

4.75 V for 1 sec. or more.

2. The yaw rate sensor open circuit detect signal is ON for

1 sec. or more.

3. The yaw rate sensor power source voltage is out of the

range from 4.4 to 5.6 V for 1 sec. or more.

4. Momentary open circuit of the yaw rate sensor signal

occurs 10 times or more.

Yaw rate sensor

Yaw rate sensor circuit

C1234/34

When the yaw rate sensor VYS terminal voltage is 4.4 to
5.6 V, YD malfunction signal of the yaw rate sensor is ON
for 5 sec. or more.

WIRING DIAGRAM

055VY-02