Lexus ES300 (1997 year). Manual - part 436

N21225

Cruise Control ECU

PI

O

D

D

Junction
Connector

O

IG2

5

O

4

3

R–L

D

D

Junction
Connector

R–L

Instrument Panel J/B

2

1D

1K

1

B–Y

4 IG1

AM1

Ignition Switch

2

W

Instrument Panel J/B

AM1

GAUGE

2

1K

1

1B

B–R

1

ALT

FL BLOCK

1

B–G

FL MAIN

Battery

CRUISE MAIN
Indicator Light
(in Combination Meter)

J2

C7

C10

J4

F11

F6

4

C14

2

1

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

DI–521

673

1997 LEXUS ES300   (RM511U)

CRUISE MAIN Indicator Light Circuit

CIRCUIT DESCRIPTION

When the cruise control main switch is turned ON, CRUISE MAIN indicator light lights up.

WIRING DIAGRAM

DI0FD–01

AB0119
N19927

I00746

ON

PI

(–)

(+)

DI–522

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

674

1997 LEXUS ES300   (RM511U)

INSPECTION PROCEDURE

1

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

PREPARATION:
Tun ignition switch ON.
CHECK:
Measure voltage between terminals PI and GND of cruise con-
trol ECU connector when main switch on and off.
OK:

Switch position

Voltage

OFF

10 – 16 V

ON

Below 1.2 V

OK

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

DI–487

).

NG

2

Check combination meter (See page 

BE–2

).

NG

Replace combination meter.

OK

Check and replace cruise control ECU 
(See page 

IN–27

).

N21234

Cruise Control ECU

4

5

TC

O

LG–R

D

D

Junction
Connector

B

B

BR

3

A

DLC3

IK3

10

BR

11

DLC1

J2

6

J8

J1

ED

PI

C14

C14

O

J9

A

A

LG–R

3

A/D

E1

E1

TC

Junction
Connector

BR

Junction
Connector

J24

Junction
Connector

B

C

BR

D3

D1

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

DI–523

675

1997 LEXUS ES300   (RM511U)

Diagnosis Circuit

CIRCUIT DESCRIPTION

This circuit sends a signal to the ECU that DTC output is required.

WIRING DIAGRAM

INSPECTION PROCEDURE

DI0FF–01

AB0119
S−17−1

I00747

ON

TC

E1

DLC2

DI–524

–

DIAGNOSTICS

CRUISE CONTROL SYSTEM

676

1997 LEXUS ES300   (RM511U)

1

Check voltage between terminals Tc and E

1 

of DLC2.

PREPARATION:
Turn ignition switch ON.
CHECK:
Measure voltage between terminals Tc and E

1

 of DLC2.

OK:

Voltage: 10 – 14 V

OK

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

DI–487

).

NG

2

Check harness and connector between cruise control ECU and DLC2, DLC2 and
body ground (See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and replace cruise control ECU 
(See page 

IN–27

).