Lexus ES300 (1997 year). Manual - part 339

–

DIAGNOSTICS

ENGINE

DI–133

285

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

HINT:This diagnostic chart is based on the premise that the engine is cranked normally. If the engine is not
cranked, proceed to the problem symptoms table on page 

DI–22

.

 hand–held tester

1

Connect LEXUS hand–held tester and check STA signal.

PREPARATION:
(a)

Connect the LEXUS hand–held tester to the DLC3.

(b)

Turn ignition switch ON and push the LEXUS hand–held tester main switch ON.

CHECK:
Read STA signal on the LEXUS hand–held tester while starter operates.
OK:

Ignition switch position

ON

START

STA signal

OFF

ON

OK

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

DI–22

).

NG

2

Check for open in harness and connector between ECM and starter relay
(See page 

IN–27

).

NG

 Repair or replace or connector.

OK

Check and replace ECM (See page 

IN–27

).

A00242

START

STA(+)

BE6653
S04163

DI–134

–

DIAGNOSTICS

ENGINE

286

1997 LEXUS ES300   (RM511U)

OBD II scan tool (excluding LEXUS hand–held tester)

1

Check voltage between terminal STA of ECM connector and body ground.

PREPARATION:
Remove the glove compartment (See page 

SF–65

).

CHECK:
Measure voltage between terminal STA of ECM connector and
body ground during engine cranking.
OK:

Voltage:  6 V or more

OK

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

DI–22

).

NG

2

Check for open in harness and connector between ECM and starter relay
(See page 

IN–27

).

NG

 Repair or replace harness or connector.

OK

Check and replace ECM (See page 

IN–27

).

S06672

Ignition
Switch

Instrument Panel J/B

B–R

W–R

B–R

W–R

IGN

3

7

5

5

1K

1K

7

6

1W

1B

B–Y

2L

2J

2K

2F

2A

AM2

1

4

4

2

7

1

2

3

5

EFI

EFI
Relay

B

1

1

F8

F6

Fusible

Link
Block

FL
MAIN

B–G

Battery

W–B

EC

ED

ECM

Junction
Connector

B

B

J28

J29

B–Y

E7

23

16

E8

A

A

Junction
Connector

J24

E1

BR

BR

+B

Engine Room
J/B

–

DIAGNOSTICS

ENGINE

DI–135

287

1997 LEXUS ES300   (RM511U)

ECM Power Source Circuit

CIRCUIT DESCRIPTION

When the ignition switch is turned ON, battery positive voltage is applied to the coil, closing the contacts of
the EFI main relay (Marking: EFI) and supplying power to the terminal 

+

B of the ECM.

WIRING DIAGRAM

DI0A8–01

A00243

ON

E1(–)

+B(+)

BE6653
P23885

DI–136

–

DIAGNOSTICS

ENGINE

288

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

1

Check voltage between terminals 

+

 B and E1 of ECM connectors.

PREPARATION:
(a)

Remove the glove compartment (See page 

SF–64

).

(b)

Turn ignition switch ON.

CHECK:
Measure voltage between terminals 

+

 B and E1 of ECM con-

nectors.
OK:

Voltage:  9 

∼

 14 V

OK

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

DI–22

).

NG

2

Check for open in harness and connector between terminal E1 of ECM and body
ground (See page 

IN–27

).

NG

 Repair or replace harness or connector.

OK

3

Check EFI main relay (Marking: EFI) (See page 

SF–47

).

NG

 Replace EFI main relay.

OK

4

Check EFI fuse (See page 

DI–126

, 

DI–3

).

NG

 Check for short in all the harness and
 components connected to EFI fuse.

OK