Lexus ES300 (1997 year). Manual - part 381

F00062

ECM

ABS & TRAC ECU

NEO

NEO

E7

A20

BR–W

19

15

ECM

ABS & TRAC ECU

NEO

NEO

E7

A20

BR–W

19

15

ECM

ABS & TRAC ECU

NEO

NEO

E7

A20

BR–W

19

15

ECM

ABS & TRAC ECU

NEO

NEO

E7

A20

BR–W

19

15

ECM

ABS & TRAC ECU

NEO

NEO

E7

A20

BR–W

19

15

–

DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

DI–301

453

1997 LEXUS ES300   (RM511U)

DTC

44

NE Signal Circuit

CIRCUIT DESCRIPTION

The ABS & TRAC ECU receives engine speed signals (NE signals) from the ECM.

DTC No.

DTC Detecting Condition

Trouble Area

44

Condition (1) or (2) is detected:

(1) TRAC is in operation and engine speed is 0 rpm 

     continues for 2.4 sec. or more.

(2) TRAC is in non–operation, sift lever is not in P or N

    position, both the front right and left wheels’ speed 

     is 30 km/h (19 mph) or more, engine speed is 0 rpm 

     and does not have communication malfunction, and 

     malfunction information of engine system is OFF.

NEO circuit

ECM

ABS & TRAC ECU

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check for open and short in harness and connector between terminal NEO of
ABS & TRAC ECU and terminal NEO of ECM (See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

DI0C8–01

F00061

NEO

(+)

(–)

ON

F00011

(Reference)

3 – 6 V

Below 1 V

3 ms. 3 ms.

(Reference)

3 – 6 V

Below 1 V

3 ms. 3 ms.

(Reference)

3 – 6 V

Below 1 V

3 ms. 3 ms.

DI–302

–

DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

454

1997 LEXUS ES300   (RM511U)

2

Check voltage between terminal NEO of ABS & TRAC ECU and body ground.

PREPARATION:
(a)

Remove ABS & TRAC ECU with connectors still con-
nected.

(b)

Turn ignition switch ON.

CHECK:
Measure voltage between terminal NEO of ABS & TRAC ECU
and body ground for the engine conditions below.
OK:

Engine condition

Voltage

OFF (IG ON)

3 – 6 V or below 1 V

ON (Idling)

2 – 3 V (Pulse)

G

Check and replace ABS & TRAC ECU or ECM.

OK

If the same code is still output after the DTC is deleted, check the contact condition of each con-
nection.

F00105

STOP

7

1C

4

W

1R

Stop 
Light 
Switch

J27

5

2

ABS & TRAC ECU

A20

Instrument Panel J/B

F11

1B

1

G–W

1S

STP

F6

ALT

B–R

A

16

R6

7

1

BP

R8

W–B

Battery

MAIN

FL Block

BM

B–G

1

1

1R

4

2

Instrument 
Panel J/B

G–W

G–W

G–W

Light 
Failure 
Sensor

Right 
Stop 
Light

High 
Mounted 
Stop 
Light

J37

Left 
Stop 
Light

R

H11

2

1

H11

R6

R8

1

2

3

W–B

W–B

W–B

W–B

W–B

W–B

J/C

A

J/C

A

3

1

–

DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

DI–303

455

1997 LEXUS ES300   (RM511U)

DTC

    49

Stop Light Switch Circuit

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

49

Battery voltage has never exceed more than 17.0 V and

become less than 9.5 V within 2.16 sec. and the STP 

terminal voltage of ECU is under open circuit detecting

limits continues for 3 sec. or more.

Stop light switch

Stop light switch circuit

ECU

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check operation of stop light.

CHECK:
Check that stop light lights up when brake pedal is depressed and turns off when brake pedal is released.

NG

Repair stop light circuit (See page 

BE–50

).

OK

DI0CA–01

F00060

STP

(+)

(–)

DI–304

–

DIAGNOSTICS

ABS & TRACTION CONTROL SYSTEM

456

1997 LEXUS ES300   (RM511U)

2

Check voltage between terminal STP of ABS & TRAC ECU and body ground.

PREPARATION:
Remove ABS & TRAC ECU with connectors still connected.
CHECK:
Measure voltage between terminal STP of ABS & TRAC ECU
and body ground when brake pedal is depressed.
OK:

Voltage: 8 – 14 V

OK

Proceed to next circuit inspection shown on
problem symptoms table (See page 

DI–282

).

NG

3

Check for open in harness and connector between ABS & TRAC ECU and stop
light Switch (See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and replace ABS & TRAC ECU.