Lexus ES300 (2002 year). Manual - part 392

05-166

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

319

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

OBDII scan tool (excluding Hand-held Tester):

1

CHECK OPERATION OF OCV (See page 

10-2

)

NG

REPLACE OCV

OK

2

INSPECT ECM (See page 

05-152

)

NG

CHECK AND REPLACE ECM

OK

3

CHECK HARNESS AND CONNECTOR(OCV  -  ECM)

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

CHECK FOR INTERMITTENT PROBLEMS

A60859

W

7

1

Battery

FL MAIN

W-R

B-G

W-B

Starter

1L

ECM

IF6

Driver 
Side 
J/B

ALT

EC

2

8

B-Y

B-W

G-Y

W-R

B-G

B-G

1

B-R

1

S2

7

3 1C

B-R

W-B

B-R

1

1

1

1

1

2

3

5

ST1

ST2

AM1

AM2

IF6

5

IF3 3

1

1

1

2

1

2

2

2

2

AM2

AM1

1A

1E

2E

2A

Ignition SW

1K

1H

8

8

1J

1L

9

6

E9 STA

Engine 
Room 
R/B

7

9

Engine 
Room 
R/B

Engine 
Room 
J/B

S3

7

9

8

E9 NSW

Park/
Neutral 
Position 
SW

Engine 
Room 
J/B

1K

7

B-W

G-Y

Engine 
Room 
J/B

G-Y

G-Y

G-Y

B-Y

B-Y

B-Y

ST 
Relay

Engine 
Room 
J/B

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-167

320

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

STARTER SIGNAL CIRCUIT

CIRCUIT DESCRIPTION

When the engine is cranked, the intake air flow is slow, so fuel vaporization is poor. A rich mixture is therefore
necessary in order to achieve good startability. While the engine is being cranked, the battery positive volt-
age is applied to terminal STA of the ECM. The starter signal is mainly used to increase the fuel injection
volume for the starting injection control and after-start injection control.

WIRING DIAGRAM

051MT-11

A53763

STA

E2

05-168

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DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

321

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

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 

05-30

.

Hand-held  Tester:

1

READ VALUE OF HAND-HELD TESTER(STARTER SIGNAL)

(a)

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

(b)

Read the STA signal on the hand-held tester while the starter operates.
Result:

Ignition Switch Position

ON

START

STA Signal

OFF

ON

OK

PROCEED TO NEXT CIRCUIT INSPECTION
SHOWN ON PROBLEM SYMPTOMS TABLE

NG

2

CHECK HARNESS AND CONNECTOR(ECM  -  STARTER RELAY)

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

CHECK AND REPLACE ECM

OBDII scan tool (excluding Hand-held Tester):

1

INSPECT ECM

(a)

Measure the voltage between terminal STA and E2 of the
ECM connector during the engine cranking.
Voltage: 6 V or more

OK

PROCEED TO NEXT CIRCUIT INSPECTION
SHOWN ON PROBLEM SYMPTOMS TABLE

NG

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-169

322

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

2

CHECK HARNESS AND CONNECTOR(ECM  -  STARTER RELAY)

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

CHECK AND REPLACE ECM