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Lexus ES300 (1997 year). Manual - part 376

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DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

DI–281

433

1997 LEXUS ES300 (RM511U)

TRC+ (A20 – 13) – GND (A19 – 15, A21 – 9, 10)

Pulse generation

TRAC control active

TRC– (A20 – 5) – GND (A19 – 15, A21 – 9, 10)

Pulse generation

TRAC control active

IND (A20

GND (A19

15 A21

9 10)

Below 2.0

IG switch ON, SLIP indicator light ON

IND (A20 – 3) – GND (A19 – 15, A21 – 9, 10)

10 – 14

IG switch ON, SLIP indicator light OFF

WT (A20

12)

GND (A19

15 A21

9 10)

Below 2.0

IG switch ON, TRAC OFF indicator light ON

WT (A20 – 12) – GND (A19 – 15, A21 – 9, 10)

10 – 14

IG switch ON, TRAC OFF indicator light OFF

CSW (A20

11)

GND (A19

15 A21

9 10)

Below 2.0

IG switch ON, TRAC cut switch pushed in

CSW (A20 – 11) – GND (A19 – 15, A21 – 9, 10)

8 – 14

IG switch ON, TRAC cut switch released

DI0C1–01

DI–282

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DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

434

1997 LEXUS ES300 (RM511U)

PROBLEM SYMPTOMS TABLE

If a normal code is displayed during the DTC check but the problem still occurs, check the circuits for each
problem symptom in the order given in the table below and proceed to the relevant troubleshooting page.

Symptoms

Inspection Circuit

See page

ABS does not operate.

Only when 1.

∼

4. are all normal and the problem is still occurring, replace the

ABS ECU.

1. Check the DTC reconfirming that the normal code is output.

2. IG power source circuit.

3. Speed sensor circuit.

4. Check the ABS & TRAC actuator with a checker.

If abnormal, check the hydraulic circuit for leakage (See page

ABS does not operate

efficiently.

Only when 1.

∼

4. are all normal and the problem is still occurring, replace the

ABS ECU.

1. Check the DTC reconfirming that the normal code is output.

2. Speed sensor circuit.

3. Stop light switch circuit.

4. Check the ABS & TRAC actuator with a checker.

If abnormal, check the hydraulic circuit for leakage (See page

ABS warning light

abnormal.

1. ABS warning light circuit.

2. ABS & TRAC ECU.

DI–310

DI–308

DTC check cannot be done.

Only when 1. and 2. are all normal and the problem is still occurring, replace the

ABS & TRAC ECU.

1. ABS warning light circuit.

2. TRAC OFF indicator light circuit.

3. Tc terminal circuit.

DI–310

DI–317

DI–313

Speed sensor signal check

cannot be done.

1. Ts terminal circuit.

2. ABS & TRAC ECU.

DI–315

DI–308

TRAC does not operate.

Only when inspection circuits for each problem symptom are all normal and the

problem is still occurring, replace the ABS & TRAC ECU.

1. Check the DTC, reconfirming that the normal code is output.

2. IG power source circuit.

3. Check the hydraulic circuit for leakage.

4. Speed sensor circuit.

SLIP indicator light

abnormal.

SLIP indicator light circuit.

DI–320

TRAC OFF indicator light

abnormal.

Only when inspection circuits for each problem symptom are all normal and the

problem is still occurring, replace the ABS & TRAC ECU.

1. TRAC OFF indicator light circuit.

2. TRAC cut switch circuit.

DI–317

DI0C2–01

F00081

ABS

ALT

ABS & TRAC
Solenoid Relay

B–G

Engine Room R/B No. 3

FL
Block

MAIN

Battery

ABS & TRAC
Actuator

DLC1

GR–R

A19

ABS & TRAC
ECU

R+

AST

W–L

W–B

B–G

W–B

A19

ABS & TRAC
ECU

ABS

ALT

ABS & TRAC
Solenoid Relay

B–G

Engine Room R/B No. 3

FL
Block

MAIN

Battery

ABS & TRAC
Actuator

DLC1

GR–R

A19

ABS & TRAC
ECU

R+

AST

W–L

W–B

B–G

W–B

A19

ABS & TRAC
ECU

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DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

DI–283

435

1997 LEXUS ES300 (RM511U)

CIRCUIT INSPECTION

DTC

11, 12

ABS & TRAC Solenoid Relay Circuit

CIRCUIT DESCRIPTION

This relay supplies power to each ABS & TRAC solenoid. After the ignition switch is turned ON, if the initial
check is OK, the relay goes on.

DTC No.

DTC Detecting Condition

Trouble Area

Condition (1) to (3) are detected:

(1) Malfunction of solenoid relay monitor.

(2) Battery voltage will not exceed more than 17.0 V

within 2.16 sec.

(3) Battery voltage will not become less than 9.5 V within

2.16 sec., or after the solenoid relay is ON and AST

voltage of ECU terminal does not become 8.0 V or

more.

ABS & TRAC solenoid relay

ABS & TRAC solenoid relay circuit

ECU

Solenoid relay is OFF in the midst of premain routine, and

AST voltage of ECU terminal is 8.0 V or more continues

for 2.04 sec. or more.

Fail safe function: If trouble in the ABS & TRAC solenoid relay circuit, the ECU cuts off current to the ABS
& TRAC solenoid relay and prohibits ABS control and TRAC control.

WIRING DIAGRAM

F00048

(+)

(–)

1 2

Engine Room
R/B No. 3

4 5 6

(+)

(–)

1 2

Engine Room
R/B No. 3

4 5 6

(+)

(–)

1 2

Engine Room
R/B No. 3

4 5 6

(+)

(–)

1 2

Engine Room
R/B No. 3

4 5 6

F00055

ABS & TRAC
Solenoid
Relay

A19

AST

ABS & TRAC

Actuator

ECU

ABS & TRAC
Solenoid
Relay

A19

AST

ABS & TRAC

Actuator

ECU

ABS & TRAC
Solenoid
Relay

A19

AST

ABS & TRAC

Actuator

ECU

ABS & TRAC
Solenoid
Relay

A19

AST

ABS & TRAC

Actuator

ECU

DI–284

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DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

436

1997 LEXUS ES300 (RM511U)

INSPECTION PROCEDURE

Check voltage between terminals 1 and 2 of Engine Room R/B No. 3 (for ABS &
TRAC solenoid relay).

PREPARATION:
Remove ABS & TRAC solenoid relay from Engine Room R/B
No. 3.
CHECK:
Measure the voltage between terminals 1 and 2 of Engine
Room R/B No. 3 (for ABS & TRAC solenoid relay).
OK:

Voltage: 10 – 14 V

Check and repair harness or connector.

Check continuity between terminal 3 of ABS & TRAC solenoid relay and terminal
AST of ABS & TRAC ECU.

CHECK:
Check continuity between terminal 3 of ABS solenoid relay and
terminal AST of ABS & TRAC ECU.
OK:

Continuity

HINT:There is a resistance of 33

Ω

between terminals A7 – 4

and A7 – 5 of ABS actuator.

Repair or replace harness or ABS & TRAC
actuator.

Content .. 374 375 376 377 ..