Lexus ES300 (1997 year). Service manual — part 341

A00245

ON

FC(+)

BE6653
P23888

–

DIAGNOSTICS

ENGINE

DI–141

293

1997 LEXUS ES300 (RM511U)

4

Check voltage between terminal FC of ECM and body ground.

PREPARATION:
(a)

Remove the glove compartment (See page

SF–65

).

(b)

Turn ignition switch ON.

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

Voltage: 9

∼

14 V

NG

Check for open in harness and connector
between EFI main relay and circuit opening
relay, circuit opening relay and ECM.

OK

5

Check fuel pump (See page

SF–6

).

NG

Repair or replace fuel pump.

OK

6

Check for open in harness and connector between circuit opening relay
(Marking:CIR OPN) and fuel pump, fuel pump and body ground
(See page

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and replace ECM (See page

IN–27

).

A00246

ON

FC

BE6653
P23891
P20186

DI–142

–

DIAGNOSTICS

ENGINE

294

1997 LEXUS ES300 (RM511U)

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

1

Check operation of fuel pump.

PREPARATION:
(a)

Remove the glove compartment (See page

SF–64

).

(b)

Turn ignition switch ON.

CHECK:
(a)

Connect between terminal FC of ECM and body ground.

(b)

Check that pulsation damper screw rises up when con-
nect between terminal FC of ECM and body ground.

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

–

DIAGNOSTICS

ENGINE

DI–143

295

1997 LEXUS ES300 (RM511U)

4

Check voltage between terminal FC of ECM and body ground
(See page

DI–138

,

DI–14

).

NG

Check for open in harness and connector
between EFI main relay and circuit opening
relay, circuit opening relay and ECM.

OK

5

Check fuel pump (See page

SF–6

).

NG

Repair or replace fuel pump.

OK

6

Check for open in harness and connector between circuit opening relay and fuel
pump, fuel pump and body ground (See page

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and replace ECM (See page

IN–27

).

A00306

1

3

5

2

4

6

IACV

IACV closed (VSV: ON)

Throttle Valve

60

°

3,700 rpm
Engine speed

Throttle valve

opening angle

FI7011 FI6570

S06464

From Ignition Switch

From FL MAIN

Engine
Room

2K

2A

2F

2J

7

2

4

1

1

5

2

3

EFI

EFI

Relay

W–B

EC

B–Y

B–Y

B–Y

B–Y

B

B

J29

J28

Connector

Junction

IK3

9

A

A

Connector

Junction

J23

ECM

E01

ACIS

E8

6

R–Y

1

2

VSV for ACIS

J/B

DI–144

–

DIAGNOSTICS

ENGINE

296

1997 LEXUS ES300 (RM511U)

IACV Control VSV Circuit

CIRCUIT DESCRIPTION

This circuit opens and closes the IACV (Intake Air Control Valve) in response to the engine load in order to
increase the intake efficiency (ACIS: Acoustic Control Induction System).
When the engine speed is 3,700 rpm or less and the throttle valve opening angle is 60

°

or more, the ECM

turns the VSV ON and closes the IACV. At all other times, the VSV is OFF, so the IACV is open.

WIRING DIAGRAM

DI0AA–01