Lexus ES300 (1997 year). Service manual — part 401

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

DI–381

533

1997 LEXUS ES300 (RM511U)

2

Check harness and connector between Seat Position Control ECU and motor
(See page

IN–27

).

NG

Repair or replace harness or connector.

OK

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

DI–374

).

N21262

Reclining Position Sensor

Rear Vertical
Position Sensor

Front Vertical
Position Sensor

Slide Position
Sensor

Seat Position Control ECU

PVCC

SSRR

SSRV

SSFV

SSRS

SGND

LG–R

LG–B

LG

BR

V–W

GR

4

BR

BS2

9

V–W

BR

3

2

10

1

11

V–W

V–W

V–W

1

BR

BR

BR

BR

1

1

1

2

2

2

2

3

3

3

3

S15

IH

S15

S15

S15

S15

S15

N21254

Seat Position Control ECU

Connect

(–)

(+)

PVCC

4

DI–382

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

534

1997 LEXUS ES300 (RM511U)

Position Sensor Power Source Circuit

CIRCUIT DESCRIPTION

This circuit provides power to the slide, front vertical and reclining sensors.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

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

PREPARATION:
Remove Seat Position Control ECU with connectors still con-
nected.
CHECK:
While operating the Power Seat Control Switch and moving the
seat, check voltage between terminal PVCC of Seat Position
Control ECU connector and body ground.
OK:
Voltage: 7.2 – 8.8 V

OK

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

DI–374

).

NG

DI0G6–01

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

DI–383

535

1997 LEXUS ES300 (RM511U)

2

Check harness and connector connected to terminal PVCC of Seat Position Con-
trol ECU (See page

IN–27

).

CHECK:
Check for open or short in the harness and check connectors for the position sensor power source circuit
outlined in the diagram with a thick line (–). (See page

DI–382

)

NG

Repair or replace harness or connector.

OK

Check and replace Seat Position Control
ECU.

BE3991

1 pulse output per one
turn of motor

Position Sensor
(in Motor)

8 V

0 V

ECU

N14754

Example: Slide Motor

Motor

Sensor

(+)

2

(+)

(–)

(–)

1

3

1

2

DI–384

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM

536

1997 LEXUS ES300 (RM511U)

Position Sensor Circuit

CIRCUIT DESCRIPTION

The position sensor senses movement of the seat and send
pulse signals to the ECU. The position sensor sends pulse to
the ECU in proportion to the amount of seat movement, as
shown in the diagram on the left.
The ECU uses the number of pulses to constantly calculate the
position relative to the memory position and returns the seat to
the memorized position.
If a malfunction occurs in a position sensor and a sensor signal
is not in put to the ECU even when the motor operates, the ECU
prohibits return operation.

WIRING DIAGRAM

See page

DI–382

.

INSPECTION PROCEDURE

1

Check position sensor.

PREPARATION:
Disconnect the connector of the sensor and the connector of
the motor leading to the sensor.
CHECK:
(a)

Connect positive

lead to terminal 3 of sensor and nega-

tive

lead to terminal 2.

(b)

Measure voltage between terminal 1 of sensor and body
ground when battery positive voltage is applied between
terminals 1 and 2 of motor connector.

HINT:
When the battery positive voltage is applied the motor connec-
tor terminals,

and

are interchangeable.

OK:

Condition

Voltage

Motor stopped

(Check several times with the motor in a

different position each time.)

0 V or battery positive voltage according

to stop position.

with motor turning

half of battery positive voltage

NG

Replace position sensor.

OK

DI0G9–01