Lexus ES300 (2002 year). Manual - part 395

A53769

FC

E2

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-177

330

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

3

CHECK E.F.I. CIRCUIT OPENING RELAY ASSY (See page 

10-2

)

NG

REPLACE E.F.I. CIRCUIT OPENING RELAY
ASSY

OK

4

INSPECT ECM

(a)

Turn the ignition switch ON.

(b)

Measure the voltage between terminal FC and E2 of the
ECM connector.
Voltage: 9 - 14 V

NG

CHECK HARNESS AND CONNECTOR

OK

5

CHECK FUEL PUMP (See page 

11-4

)

NG

REPLACE FUEL PUMP

OK

6

CHECK HARNESS AND CONNECTOR(CIRCUIT OPENING RELAY - FUEL PUMP,
FUEL PUMP - E2)

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

CHECK AND REPLACE ECM

A59757

20

IF6

W - R

Ignition 
Switch

ED

W - B

IF3

1E

1C

1B

AM2

IG2

8

Engine Room J/B

E6

E8

ECM

B - W

Battey

FL MAIN

E.F.I.

2

B - G

7

8

8

9

1

8

7

1C

1C

6

1

E6

E6

B - G

1

1

B - R

B - R

IG2

AM2

2

4

3

3

3

2

1

5

E.F.I. 
ECU 
Relay

5

EF

BR

BR

A

A

B - R

B - O

B - R

W - R

5

17

Driver Side J/B

Driver Side J/B

2G

2G

2G

2G

Engine Room
J/B

J11 J/C

1A

1C

B - O

IGSW

+B

MREL

E1

Engine Room R/B

05-178

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

331

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

ECM POWER SOURCE CIRCUIT

CIRCUIT DESCRIPTION

When the ignition switch is turned ON, battery positive voltage is applied to terminal IGSW of the ECM and
the E.F.I. ECU relay (Marking: E.F.I.) control circuit in the ECM sends a signal to terminal MREL of the ECM
switching on the E.F.I. ECU relay.
This signal causes current to flow to the coil, closing the contacts of the E.F.I. ECU relay and supplying power
to terminal +B of the ECM.
If the ignition switch is turned off, the ECM continues to switch on the E.F.I. ECU relay for a maximum of 2
seconds for the initial setting of the IAC valve.

WIRING DIAGRAM

056HC-03

A53769

+B

E2

A57021

E2

E1

E10

E8

A53769

E2

IGSW

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-179

332

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

INSPECT ECM

(a)

Turn the ignition switch ON.

(b)

Measure the voltage between terminals 

+

B and E2 of the

ECM connectors.
Voltage: 9 - 14 V

OK

PROCEED TO NEXT CIRCUIT INSPECTION
SHOWN ON PROBLEM SYMPTOMS TABLE

NG

2

CHECK HARNESS AND CONNECTOR(E1,E2 - BODY EARTH)

(a)

Disconnect the ECM E10 and E8 connector.

(b)

Check for open between the terminals E1 and E2 of the
ECM connector and Body ground.
Resistance: 1 

Ω 

or less

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

3

INSPECT ECM

(a)

Turn the ignition switch ON.

(b)

Measure the voltage between terminal IGSW and E2 of
the ECM connector.
Voltage: 9 - 14 V

OK

Go to step 6

NG

A59714

AM2(30A)

1

5

6

2

3

7

8

4

A56879

IG1

AM1

ST1

ACC

IG2

AM2

ST2

A53769

MREL

E2

05-180

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

333

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

4

CHECK FUSE(AM2)

(a)

Remove the AM2 fuse from the engine room J/B.

(b)

Check the continuity of the AM2 fuse.

NG

CHECK FOR SHORT IN ALL HARNESS AND
COMPONENTS CONNECTED AM2 FUSE

OK

5

CHECK IGNITION OR STARTER SWITCH ASSY

(a)

Check continuity between the connector terminals shown
in the chart below.

Switch

Terminal No.

Resistance

LOCK

All Terminal to Terminal

1M

Ω

 or more

ACC

2

⇔

3

1

Ω

 or less

ON

2

⇔

3

⇔

4

6

⇔

7

1

Ω

 or less

START

1

⇔

2

⇔

4

6

⇔

7

⇔

8

1

Ω

 or less

NG

REPLACE IGNITION OR STARTER SWITCH
ASSY

OK

REPAIR OR REPLACE HARNESS AND CONNECTOR

6

INSPECT ECM

(a)

Turn the ignition switch ON.

(b)

Measure the voltage between terminal MREL and E2 of
the ECM connector.
Voltage: 9 - 14 V

NG

CHECK AND REPLACE ECM

OK