Toyota Sequoia (2005). Manual - part 432

I28701

Wire Harness Side:
Lumbar Support Control Switch

L4

I28702

Lumbar Support Control Motor

Clockwise

Counter-
clockwise

Driving Axis

L3

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM (w/ Driving Position 
Memory)

DI–1523

1717

3

Check harness and connector (Power source).

CHECK:
Measure the voltage of each terminal of the wire harness side
connectors.
OK:

Tester Connection

Condition

Specified Condition

L4–3 – Body ground

Always

10 to 14 V

CHECK:
Measure the resistance of each terminal, as shown in the il-
lustration and table.
OK:

Tester Connection

Condition

Specified Condition

L4–2 – Body ground

Always

Below 1 

Ω

L4–5 – Body ground

Always

Below 1 

Ω

NG

Repair or replace harness or connector.

OK

4

Inspect lumbar support control motor.

PREPARATION:
Remove the lumbar support control motor (See page 

BO–112

).

CHECK:
Check that the motor rotates smoothly when the battery is con-
nected to the lumbar support control motor connector terminals.
OK:

Measurement Condition

Operational Direction

Battery positive (+) 

→

1

Battery negative (–) 

→

 2

Clockwise

Battery positive (+) 

→

 2

Battery negative (–) 

→

 1

Counterclockwise

NG

Replace lumbar support control motor
(See page 

BO–112

).

OK

I28701

Wire Harness Side:
Lumbar Support Control Switch

L4

I28555

Wire Harness Side:
Lumbar Support 
Control Motor

L3

DI–1524

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM (w/ Driving Position 
Memory)

1718

5

Check harness and connector (Lumbar support control switch – lumbar support
control motor).

CHECK:
Measure the resistance of each terminal, as shown in the il-
lustration and table.
OK:

Tester Connection

Condition

Specified Condition

L4–1 – L3–2

Always

Below 1 

Ω

L4–4 – L3–1

Always

Below 1 

Ω

L4–1 – Body ground

Always

10 k

Ω

 or higher

L4–4 – Body ground

Always

10 k

Ω

 or higher

NG

Repair or replace harness or connector.

OK

Proceed to next circuit inspection shown in
problem symptoms table (See page 

DI–1508

).

I28449

Position Control
ECU & Switch

SLD–

SLD+

FRV–

FRV+

LFT–

LFT+

RCL–

RCL+

2

1

2

1

2

1

2

1

3

M7

M7

M7

M7

M7

M7

M7

M7

2

4

6

9

7

10

8

BR

P14
Power Seat Motor
(Driver’s Seat Front Vertical Control)

P16
Power Seat Motor
(Driver’s Seat Reclining Control)

P

V

W

B

G

Y

L

P15
Power Seat Motor
(Driver’s Seat Rear Vertical Control)

P17
Power Seat Motor
(Driver’s Seat Slide Control)

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM (w/ Driving Position 
Memory)

DI–1525

1719

Power seat motor circuit

CIRCUIT DESCRIPTION

When the power seat control switch is operated, a command signal is sent to the position control ECU. The
position control ECU then controls the appropriate seat motor as needed. This memory system does not use
a seat position sensor. The seat position is detected by counting pulses that are output when the motor turns.
If there is no pulse output from the motor, the motor will stop operating. The ECU is designed so that a mal-
function of the seat memory system will not interfere with manual seat control.
When the position control ECU switch assy detects the low motor speed or abnormal activity, the system
stops the motor. When the motor continuously operates for 120 seconds or more, the system will stop the
motor until the switch is turned off.

WIRING DIAGRAM

DIDEB–01

I07253

1

2

1

2

DI–1526

–

DIAGNOSTICS

POWER SEAT CONTROL SYSTEM (w/ Driving Position 
Memory)

1720

INSPECTION PROCEDURE

1

Inspect power seat motor assy.

PREPARATION:
Remove the power seat motor (See page 

BO–112

).

CHECK:
Check that the motor rotates smoothly when the battery is con-
nected to the connector terminal.
OK:

Tester Connection

Specified Condition

Battery positive voltage – 1

Battery negative voltage – 2

Counterclockwise

Battery positive voltage – 2

Battery negative voltage – 1

Clockwise

NG

Replace power seat motor (See page 

BO–112

).

OK