Lexus ES300 (1997 year). Manual - part 420

DI0DW–01

N21275

Wireless Door Lock ECU

SHORT PIN

1W

1G

DOME

Engine Room J/B

Battery

+B

J5

J6

W–B

J16

A

GND

B

8

FL MAIN

A

R

A

A

1

12

2J

R

8

Instrument panel J/B

J/C

W–B

W8

W8

7

1

2A

R

IG

N14677

Fuse

–

DIAGNOSTICS

WIRELESS DOOR LOCK CONTROL SYSTEM

DI–457

609

1997 LEXUS ES300   (RM511U)

CIRCUIT INSPECTION

 ECU Power Source Circuit

CIRCUIT DESCRIPTION

Battery positive voltage is always applied the terminal +B of the wireless door lock ECU.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check DOME fuse.

PREPARATION:
Remove DOME fuse from engine room junction block.
CHECK:
Check continuity of DOME fuse.
OK:

Below 1.0 

Ω

 or continuity

NG   

Check for short in all the harness and compo-
nents connected to DOME fuse.
(See attached wiring diagram.)

OK

N22142

+B(+)

DI–458

–

DIAGNOSTICS

WIRELESS DOOR LOCK CONTROL SYSTEM

610

1997 LEXUS ES300   (RM511U)

2

Check voltage between terminals +B and ECU connector.

PREPARATION:
Remove the wireless door lock ECU from No.1 instrument pan-
el brace.
CHECK:
Measure voltage between terminals +B of ECU connector.
OK:

Voltage: 10 – 14 V

OK

Proceed to next circuit inspection shown on
matrix chart (See page 

DI–456

).

NG

3

Check for open in harness and connector between terminal GND of ECU and
body ground (See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and repair harness and connector be-
tween ECU and battery.

N21274

Instrument Panel J/B

Ignition Switch

Wireless Door Lock ECU

AM1

J6

W8

F11

Battery

B–Y

B–R

1D

1K

ECU–IG

FL MAIN

AL

T

Instrument Panel J/B

F6

J6

B–R

B–R

B

B

4

2

W

1K

1B

1

2

13 IG

1

2

N14677

–

DIAGNOSTICS

WIRELESS DOOR LOCK CONTROL SYSTEM

DI–459

611

1997 LEXUS ES300   (RM511U)

Ignition Switch Circuit

CIRCUIT DESCRIPTION

When the ignition switch is turned to the ON position, battery positive voltage is applied to the terminal IG
of the ECU. Furthermore, power supplied from the terminal IG of the ECU is used as power for the wireless
door lock buzzer.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check ECU–IG fuse.

PREPARATION:
(a)

Remove front lower panel.

(b)

Remove ECU–IG fuse from instrument panel junction
block.

CHECK:
Check continuity of ECU–IG fuse.
OK:

Continuity

NG   

Check for short in all the harness and compo-
nents connected to ECU–IG fuse.
(See attached wiring diagram.)

OK

DI0DX–01

AB0119

N22141

I00639

IG(+)

ON

DI–460

–

DIAGNOSTICS

WIRELESS DOOR LOCK CONTROL SYSTEM

612

1997 LEXUS ES300   (RM511U)

2

Check voltage between terminal IG of ECU and body ground.

PREPARATION:
(a)

Disconnect the ECU connector.

(b)

Turn the ignition switch ON.

CHECK:
Measure voltage between terminals IG of ECU connector and
body ground.
OK:

Voltage: 10 

∼

 14 V

OK

Check and replace ECU.

NG

Check and repair harness and connector be-
tween ECU and battery (See page 

IN–27

).