Lexus ES300 (1997 year). Service manual - part 403

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

DI–389

541

1997 LEXUS ES300   (RM511U)

2

Check voltage between terminal P of Seat Position Control ECU connector and
body ground.

PREPARATION:
Remove Seat Position Control ECU with connectors still con-
nected.
CHECK:
(a)

Turn ignition switch ON.

(b)

Measure voltage between terminal P of Seat Position
Control ECU connector and body ground when the shift
lever is positioned to the following ranges.

OK:

Shift position

Voltage

P

10 

∼

 14 V

Other than P

0 V

OK

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

DI–374

).

NG

Check and repair harness and connector be-
tween Seat Position Control ECU and park/
neutral position switch.

N21265

Instrument Panel J/B

Seat Position Control ECU

Ignition Switch

Battery

ALT

J/C

F6

Instrument Panel J/B

FL

3

IG

20

B–R

W

B–R

4

B–R

B–R

B–Y

4

2

2

1

1

FL MAIN

2

S15

IF1

1K

1K

F11

BS2

1D

1K

8

1

AM1

B–R

B–G

ECU–B

N21256

Seat Position Control ECU

ON

LOCK

Connect

(–)

(+)

20

IG

ON

LOCK

DI–390

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

542

1997 LEXUS ES300   (RM511U)

Ignition Switch Circuit

CIRCUIT DESCRIPTION

This circuit sends an ignition switch ON or OFF signal to the ECU.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check voltage between terminal IG of Seat Position Control ECU connector and
body ground.

PREPARATION:
Remove Seat Position Control ECU with connectors still con-
nected.
CHECK:
Measure voltage between terminal IG of Seat Position Control
ECU connector and body ground when ignition switch is on and
off.
OK:

Ignition switch

Voltage

ON

10 

∼

 14 V

OFF

0 V

OK

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

DI–374

).

DI0GF–01

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

DI–391

543

1997 LEXUS ES300   (RM511U)

NG

2

Check ECU–IG fuse.

NG

Check for short in all the harness and compo-
nents connected to ECU–IG fuse.

NG

Check and repair harness or connector be-
tween Seat Position Control ECU and battery.

N21266

Power Seat Control Switch

Power Seat Control ECU

SLDF

SLDR

RUP

RDWN

FUP

FDWN

RCLF

RCLR

12

L

BR

8

SGND

13

14

15

16

17

18

19

11

L–B

Y–G

L–Y

L–R

G

G–B

BR

BR

4

2

3

10

9

1

5

12

8

S15

S15

S15

S15

S15

S15

S15

S15

S15

G–W

BS2

IH

N21257

Seat Position Control ECU

SLDF

SLDR

RUF

RDWN

FUR

FDWN

RCLF
RCLR

SGND

(–)

(+)

Connect

DI–392

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

544

1997 LEXUS ES300   (RM511U)

Power Seat Control Switch Circuit

CIRCUIT DESCRIPTION

When the power seat control switch is operated, a signal is sent from the power seat control switch to the
ECU and the ECU sends a signal to the motor to make it operate.
Even if a malfunction should occur with the position sensor and return operation is prohibited, manual opera-
tion will occur as normal.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check voltage between each terminal of the Power Seat Control Switch and
SGND of Seat Position Control ECU connector.

PREPARATION:
Remove Seat Position Control ECU with connectors still con-
nected.
CHECK:
Measure voltage between each terminal of the Power Seat
Control Switch and SGND of Seat Position Control ECU con-
nector. (The illustration shows inspection of the reclining as an
example.)
OK:

At each terminal with switch ON

0 V

At each terminal with switch OFF

10 

∼

 14 V

DI0GG–01