Lexus SC300 / Lexus SC400. Manual - part 139

ELECTRIC TENSION REDUCER
SYSTEM

Parts Location

Wiring and Connector Diagrams

–

BODY ELECTRICAL SYSTEM

Electronic Tension Reducer System

BE–167

Parts Inspection
(Tension Reducer Solenoid)
REMOVAL AND INSTALLATION OF
TENSION REDUCER SOLENOID

(See page 

BO–71

)

INSPECTION OF TENSION REDUCER
SOLENOID

INSPECT TENSION REDUCER SOLENOID

(Operation)
(a) Connect 

the positive (+) lead from the battery to terminal

2, and negative (–) lead to terminal 1.

(b)  Pull the belt upward and check that the belt is slowly

retracted when released.

(c)  Disconnect the lead from the battery.
(d)  Pull the belt upward and check that the belt is retracted

more quickly when released than in (b).

HINT: Do not tilt the retractor.
If the operation is not as specified, replace the front seat outer
belt assembly.

(Circuit)
Disconnect the tension reducer solenoid connector and in-
spect the connector on wire harness side as shown.

Check for

Tester connection

Condition

Specified value

Voltage

2–Ground

Ignition switch

ON

Battery voltage

g

g

position

ACC or LOCK

No voltage

Continuity

1–Ground

Buckle switch position

ON (belt fastened)

Continuity

y

OFF (belt unfastened)

No continuity

If the circuit is specified, replace the front seat outer belt as-
sembly.
If the circuit is not as specified, refer to 

BE–167

 wiring dia-

gram, and inspect the circuits connected to other parts.

BE–168

–

BODY ELECTRICAL SYSTEM

Electric Tension Reducer System

(Buckle Switch)
REMOVAL AND INSTALLATION OF
BUCKLE SWITCH

1. 

REMOVE BUCKLE SWITCH
(a)  Remove the driver or front passenger’s seat.
(b)  Disconnect buckle switch connector.
(c)  Remove seat belt inner with buckle switch.

2. 

INSTALL BUCKLE SWITCH

For installation follow the removal procedure in reverse.

INSPECTION OF BUCKLE SWITCH

INSPECT BUCKLE SWITCH

(Switch Continuity)
(a)  Check that there is continuity between terminals on the

switch side connector with  the switch  ON (belt
fastened).

(b)  Check that there is no continuity between terminals on

the switch side connector with the switch OFF (belt
unfastened).

If operation is not as specified, replace the seat belt inner.

(Switch Circuit)
Disconnect the connector from switch and inspect the con-
nector on wire harness side as shown.

Check for

Tester connection

Condition

Specified value

Voltage

2–Ground

Ignition switch posi-

ON

Battery voltage

g

g

tion

ACC or LOCK

No voltage

Continuity

1–Ground

Constant

Continuity

If the circuit is not as specified, refer to 

BE–167

 wiring dia-

gram, and inspect the circuits connected to other parts.

–

BODY ELECTRICAL SYSTEM

Electric Tension Reducer System

BE–169

Troubleshooting

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

See page

BE–4

,20

BE–168

BE–169

    –

–

Trouble

Parts

name

GAUGE Fuse

T

ension Reducer Solenoid

Buckle Switch

Wire Harness

Tension Reducer does not operate.
(Driver’s and Passenger’s)

1

2

Tension Reducer does not operate. (Only one side)

2

1

3

BE–170

–

BODY ELECTRICAL SYSTEM

Electric Tension Reducer System