Lexus ES300 (1997 year). Manual — part 340

S04164

IGN Fuse

Instrument Panel J/B

–

DIAGNOSTICS

ENGINE

DI–137

289

1997 LEXUS ES300 (RM511U)

5

Check for open in harness and connector between EFI main relay (Marking: EFI)
and battery, EFI main relay (Marking: EFI) and ECM (See page

IN–27

).

NG

Repair or replace harness or connector.

OK

6

Check IGN fuse.

PREPARATION:
Remove the IGN fuse from the instrument panel J/B.
CHECK:
Check continuity of IGN fuse.
OK:

Continuity

NG

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

OK

7

Check ignition switch (See page

BE–19

).

NG

Replace ignition switch.

OK

Check for open in harness and connector be-
tween IG switch and EFI main relay, EFI main
relay and body ground (See page

IN–27

).

P19781

EFI

IGN

MAIN

IG Switch

AM2

Battery

EFI Main
Relay

Circuit Opening
Relay

Fuel Pump

Starter
Relay

Starter

Park/ Neutral Position Switch

ECM

FC

Tr

STA

NE

(STA Signal)

(NE Signal)

DI–138

–

DIAGNOSTICS

ENGINE

290

1997 LEXUS ES300 (RM511U)

Fuel Pump Control Circuit

CIRCUIT DESCRIPTION

In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to
the starter relay coil and also current flows to terminal STA of ECM (STA signal).
When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil of the circuit
opening relay, the relay switches on, power is supplied to the fuel pump and the fuel pump operates.
While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the
fuel pump also keeps operating.

DI0A9–01

S07280

ECM

E01

FC

18

G–R

EB2

L–B

G–R

IG2

1

4

EB2

L–B

7

W–B

W–B

Fuel

Pump

1 S2

Starter

B–R

EC

ID1

1

1

1

1

1

5

3

2

CIR OPN Relay

B–R

B–R

W–B

B–R

W–R

Junction

Connector

C

B

J9

J8

2C

2F

2D

2K

5

10

9

IK2

10

GR

5

6

B

B

B–W

11

IK2

Park/
Nutral
Position
Switch

J29
Junction

Connector

B–R

W–R

B–R

W–R

R

6

8

7

Ignition
Switch

ST2

AM2

1K

1B

ST
AR
TER

5

5

7

3

3

4

EFI

1J

2J

3

4

7

11

1

AM2

EFI Relay

ST Relay

2

5

1

5

3

B

B

B–G

B–G

1

1 F8

F6

Fusible

Link

Block

Engine Room R/B

Engine Room J/B

4

Instrument Panel J/B

L–B

4

5

Battery

FL MAIN

2A

2B

MAIN

2L

2K

1K

1W

3

IGN

1K

B–W

W–B

5

IK2

3 G–R

E9

BN

IG

IG2

1

2

GR

J37 Junction

Connector

–

DIAGNOSTICS

ENGINE

DI–139

291

1997 LEXUS ES300 (RM51

1

U

)

WIRING

DIAGRAM

A00244

ON

BE6653
P20186

DI–140

–

DIAGNOSTICS

ENGINE

292

1997 LEXUS ES300 (RM511U)

INSPECTION PROCEDURE

LEXUS hand–held tester

1

Connect LEXUS hand–held tester and check operation of fuel pump.

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.

(c)

Use ACTIVE TEST mode to operate the fuel pump.

CHECK:
Check that pulsation damper screw rises up when fuel pump is
on by LEXUS hand–held tester.
OK:

The pulsation damper screw rises up.

OK

Check for starter signal circuit
(See page

DI–132

).

NG

2

Check for ECM power source circuit (See page

DI–135

).

NG

Repair or replace.

OK

3

Check circuit opening relay (Marking: CIR OPN) (See page

SF–48

).

NG

Replace circuit opening relay.

OK