Lexus SC300 / Lexus SC400. Manual - part 142

Parts Inspection
(Power Window Main Relay)
INSPECTION OF POWER WINDOW MAIN
RELAY

(See Power Window Main Relay on page 

BE–152

)

(Sliding Roof Switch)
REMOVAL AND INSTALLATION OF
SLIDING ROOF SWITCH

(See Sliding Roof on page 

BO–85

)

INSPECTION OF SLIDING ROOF SWITCH

INSPECT SWITCH CONTINUITY

Terminal

Switch position

SLIDE

TILT

OFF

OPEN

CLOSE

OFF

UP

DOWN

If continuity is not as specified, replace the switch.

(Sliding Roof Motor)
REMOVAL AND INSTALLATION OF
MOTOR

(See Sliding Roof on page 

BO–85

)

INSPECTION OF MOTOR

INSPECT MOTOR OPERATION

(a)  Disconnect the connector which has 3 terminals and

inspect on the clamped connector side.

(b) Connect 

the positive (+) lead from the battery to terminal

1 and negative (–) lead to terminal 3 and check that the
motor turns clockwise.

(c) Connect 

the positive (+) lead from the battery to terminal

3 and negative (–) lead to terminal 1 and check that the
motor turns counterclockwise.

If operation is not as specified, replace the motor.
(d)  Connect the connector.

–

BODY ELECTRICAL SYSTEM

Sliding Roof Sysytem

BE–179

(Sliding Roof Control Relay)
REMOVAL AND INSTALLATION OF
SLIDING ROOF CONTROL RELAY

(See Sliding Roof on page 

BO–85

)

INSPECTION OF SLIDING ROOF
CONTROL RELAY

INSPECT CONTROL RELAY CIRCUIT

Disconnect the connector from the relay and inspect the con-
nector on the wire harness side as shown in the chart.

Check for

Test connection

Condition

Specified value

Continuity

A2 – Ground

Sliding roof control 

OFF or UP

No continuity

y

g

switch position (TILT)

DOWN

Continuity

A6 – Ground

Sliding roof control 

OFF or DOWN

No continuity

g

switch position (TILT)

UP

Continuity

A7 – Ground

Sliding roof control 

OFF or OPEN

No continuity

g

switch position (SLIDE)

CLOSE

Continuity

A8 – Ground

Sliding roof control 

OFF or CLOSE

No continuity

g

switch position (SLIDE)

OPEN

Continuity

B1 – Ground

Constant

No continuity

B1 – B3

Constant

Continuity

B2 – Ground

No. 1 limit switch 
position

OFF (Sliding roof tilt up or
approx. 200 mm (7.87 in.)
opened)

No continuity

position

ON (Except for conditions 
mentioned above)

Continuity

B3 – Ground

Constant

No continuity

B4 – Ground

Constant

Continuity

B5 – Ground

Constant

Continuity

B6 – Ground

No. 2 limit switch 

OFF (Sliding roof closed)

No continuity

position

ON (Sliding roof opened)

Continuity

Voltage

A1 – Ground

Constant

Battery voltage

g

A3 – Ground

Ignition switch position

LOCK or ACC ( * )

No voltage

g

ON

Battery voltage

(*) Except within 60 seconds after turning the ignition key to the OFF position and both the driver’s door and
the passenger’s door are closed.

If circuit is as specified, replace the relay.

BE–180

–

BODY ELECTRICAL SYSTEM

Sliding Roof System

(Sliding Roof Limit Switch)
REMOVAL AND INSTALLATION OF LIMIT
SWITCH

(See Sliding Roof on page 

BO–85

)

INSPECTION OF LIMIT SWITCH

1. 

INSPECT LIMIT SWITCH CIRCUIT

Terminal

Switch position

OFF (SW pin released)

OFF (SW pin released)

ON (SW pin pushed in)

ON (SW pin pushed in)

No. 1 limit
switch

No. 2 limit
switch

If continuity is not as specified, replace the switch.

2. 

INSPECT MOTOR WIRE CIRCUIT
(a)  Check that there is continuity between terminals A1 and

B3.

(b)  Check that there is continuity between terminals A2 and

B4.

(c)  Check that there is continuity between terminals A3 and

B1.

If continuity is not as specified, replace the switch.

(Theft Deterrent and Door Lock Control
ECU)

(See page 

BE–155

)

(Door Courtesy Switch)

(See page 

BE–79

)

–

BODY ELECTRICAL SYSTEM

Sliding Roof System

BE–181

Troubleshooting

You will find the cause of trouble more easily by properly using the table shown below. In this table, the numbers
indicate the order of priority of the causes of trouble. Check each part in the order shown. If necessary, replace
the part.

See page

BE–4

,21

BE–4

,21

BE–4

,20

BE–4

,20

BE–156

BE–152

BE–180

BE–179

BE–179

     –

–

BE–181

BE–26

BE–79

BE–4

,20

     –

–

Part

name

Trouble

AM1 Fuse

DOME Fuse

DOOR Fuse

POWER Fuse

Theft Deterrent and Door Lock Control ECU

Power Window Main Relay

Sliding Roof Control Relay

Sliding Roof Switch

Sliding Roof Motor

Sliding Rood Motor (Stones to foreign material

trapped in motor assembly)

Limit Switch

Ignition Switch

Door Courtesy Switch

ECU–IG Fuse

Wire Harness

*1

 Sliding roof system does not operate.

1

2

3

4

*2

 Sliding roof system does not operate.

3

5

4

6

7

8

9

2

1

10

Sliding roof system operates abnormally.

1

3

2

4

Sliding roof system stops operation half way.

1

3

4

2

Buzzer does not sound.

1

2

3

Buzzer sounds abnormally.

1

“Key–off Sliding Roof” operation does not
operate.

1

2

4

5

3

6

*1

: Door Lock does not operate

*2

: Door Lock is normal

BE–182

–

BODY ELECTRICAL SYSTEM

Sliding Roof System