Lexus ES300 (1997 year). Service manual - part 434

AB0119
N19920

I00743

ON

D

(–)

(+)

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

DI–513

665

1997 LEXUS ES300   (RM511U)

3

Check voltage between terminal D of cruise control ECU connector and body
ground.

PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminal D of ECU connector and
body ground when shifting into D position and other positions.
OK:

Shift Position

Voltage

D position

10 – 14 V

Other positions

Below 1 V

OK

Proceed to next circuit inspection shown on
problem symptom table (See page 

DI–487

).

NG

4

Check harness and connector between cruise control ECU and park/neutral
position switch (See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and replace cruise control ECU 
(See page 

IN–27

).

N21223

Cruise Control ECU

9

B

B–R

A

Junction
Connector

A

Instrument Panel J/B

1J

1K

B–Y

4

Ignition Switch

2

Instrument Panel J/B

AM1

1J

B–G

1B

ALT

1K

W

FL MAIN

Battery

16

GND

W–B

A

Junction
Connector

A

II

F6

B–R

1

2

IG1

1J

B–R

J3

J15

Instrument Panel J/B

J11

C14

AM1

C14

ECU–IG

1

9

J13

1

2

8

7

J9

J8

Junction Connector

2

1

A

A

W–B

DI–514

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

666

1997 LEXUS ES300   (RM511U)

ECU Power Source Circuit

CIRCUIT DESCRIPTION

The ECU power source supplies power to the actuator and sensors, etc.. When terminal GND and the cruise
control ECU case are grounded.

WIRING DIAGRAM

DI0F6–01

N20675

Instrument Panel Junction Block No.1

ECU–IG
Fuse

AB0119
N19921

I00744

ON

GND

(–)

(+)

B

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

DI–515

667

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

1

Check ECU–IG fuse.

PREPARATION:
Remove the ECU–IG fuse from instrument panel junction block
No.1.
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.

OK

2

Check voltage between terminals B and GND of cruise control ECU connector.

PREPARATION:
(a)

Remove the ECU with connector still connected.

(b)

Turn ignition switch ON.

CHECK:
Measure voltage between terminals B and GND of ECU con-
nector.
OK:

10 – 14 V

OK

Proceed to next circuit inspection shown on
problem symptom table (See page 

DI–487

).

NG

N19922

GND

DI–516

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

668

1997 LEXUS ES300   (RM511U)

3

Check resistance between terminal GND of cruise control ECU connector and
body ground.

CHECK:
Measure resistance between terminal GND of ECU connector
and body ground.
OK:

Resistance: Below 1 

Ω

NG

Repair or replace harness or connector.

OK

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

IN–27

).