Lexus ES300 (1997 year). Service manual - part 334

S05723

J22

Junction
Connector

A

A

A

A

A

IK3

B–R

B–R

B–R

W–R

12

8

3

1K

1C

Switch

Ignition

7

6

5

5

4

1

1

1

1K

1B

2L

2A

W–R

AM2

B

F8

F6

Fusible

Link
Block

B–G

FL
MAIN

Battery

B–R

G

B–R

B–R

Y

L

Ignition Coil

Spark Plug

No.1

No.2

No.3

1

1

1

2

2

2

EE

BR

3

2

1

10

9

7

6

5

4

24

16

15

12

E10

E10

E10

E10

W–R

LG–B

BR–Y

GR

Igniter

ECM

IGT1

IGT2

IGT3

IGF

5V

Instrument

Panel J/B

Engine Room
J/B

Instrument

Panel J/B

–

DIAGNOSTICS

ENGINE

DI–113

265

1997 LEXUS ES300   (RM511U)

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check spark plug and spark of misfiring cylinder (See page 

DI–57

).

NG

 Go to step 4.

OK

2

Check for open and short in harness and connector in IGF signal circuit between
ECM and igniter (See page 

IN–27

).

NG

 Repair or replace harness or connector.

OK

A00237

ON

IGF(+)

BE6653
P24326

A00238

START

IGT2  IGT3  IGT1

(+)     (+)     (+)

BE6653
P23881

DI–114

–

DIAGNOSTICS

ENGINE

266

1997 LEXUS ES300   (RM511U)

3

Disconnect igniter connector and check voltage between terminal IGF of ECM
connector and body ground.

PREPARATION:
(a)

Disconnect the igniter connector.

(b)

Remove the glove compartment (See page 

SF–64

).

(c)

Turn ignition switch ON.

CHECK:
Measure voltage between terminal IGF of ECM connector and
body ground.
OK:

Voltage:  4.5 

∼

 5.5 V

OK

 Replace igniter.

NG

Check and replace ECM (See page 

IN–27

).

4

Check for open and short in harness and connector in IGT 1 

∼

 3 signal circuits 

between ECM and igniter (See page 

IN–27

).

NG

 Repair or replace harness or connector.

OK

5

Check voltage between terminals IGT 1 

∼

 3 of ECM connector and body ground.

PREPARATION:
Remove the glove compartment (See page 

SF–64

).

CHECK:
Measure voltage between terminals IGT 1 

∼

 3 of ECM connec-

tor and body ground when engine is cranked.
OK:

Voltage:  More than 0.1 V and less than 4.5 V

P20870

IGT1 

∼

 IGT3 and IGF Signal Waveform

VOLT

5

0

5

0

5

0

5

0

IGT1

IGT2

IGT3

IGF

20 m sec./Division (Idling)

A00239

START

IGT2

(+)

IGT3

(+)

IGT1

(+)

BE6653
P23881

BE6653

P24329

A00124

ON

START

9 (+)

–

DIAGNOSTICS

ENGINE

DI–115

267

1997 LEXUS ES300   (RM511U)

Reference INSPECTION USING OSCILLOSCOPE

During idling, check waveform between terminals IGT 1 

∼

 3,

  IGF and E1 of ECM.
HINT:The correct waveforms are as shown.

NG

 Check and replace ECM (See page 

IN–27

).

OK

6

Disconnect igniter connector and check voltage between terminals IGT 1 

∼

 3 of

ECM connector and body ground.

PREPARATION:
(a)

Disconnect the igniter connector.

(b)

Remove the glove compartment (See page 

SF–64

).

CHECK:
Measure voltage between terminals IGT 1 

∼

 3 of ECM connec-

tor and body ground when engine is cranked.
OK:

Voltage:  More than 0.1 V and less than 4.5 V

NG

 Check and replace ECM (See page 

IN–27

).

OK

7

Check voltage between terminal 9 of igniter connector and body ground.

PREPARATION:
Disconnect the igniter connector.
CHECK:
Measure voltage between terminal 9 of igniter connector and
body ground, when ignition switch is turned to ”ON” and
”START” position.
OK:

Voltage:  9 

∼

 14 V

NG

 Check and repair igniter power source circuit.

OK

DI–116

–

DIAGNOSTICS

ENGINE

268

1997 LEXUS ES300   (RM511U)

8

Check for open and short in harness and connector between ignition switch and
ignition coil, ignition coil and igniter (See page 

IN–27

).

NG

 Repair or replace harness or connector.

OK

9

Check ignition coil (See page 

IG–1

).

NG

 Replace ignition coil.

OK

Replace igniter.