Infiniti FX35, FX50 (S51). Manual - part 1595

SBC-38

< DTC/CIRCUIT DIAGNOSIS >

SEAT BELT BUCKLE SWITCH (DRIVER SIDE)

 With CONSULT-III

When checking “BUCKLE SW” on DATA MONITOR of METER/M&A, check that ON/OFF display changes
synchronized with the insertion operation to the seat belt buckle.

Is the inspection result normal?

YES

>> Seat belt buckle switch (driver side) circuit is normal.

NO

>> Refer to 

SBC-38, "SEAT BELT WARNING LAMP SYSTEM : Diagnosis Procedure"

.

SEAT BELT WARNING LAMP SYSTEM : Diagnosis Procedure

INFOID:0000000005241763

1.

CHECK SEAT BELT BUCKLE SWITCH (DRIVER SIDE) CIRCUIT

1.

Turn the ignition switch ON.

2.

Check that voltage between seat belt buckle switch (driver side) harness connector and ground.

*

1

: With climate controlled seat

*

2

: Without climate controlled seat

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

CHECK SEAT BELT BUCKLE SWITCH (DRIVER SIDE) CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect combination meter connector and seat belt buckle switch (driver side) connector.

3.

Check continuity between combination meter harness connector and seat belt buckle switch (driver side)
harness connector.

*

1

: With climate controlled seat

*

2

: Without climate controlled seat

4.

Check continuity between combination meter harness connector and ground.

Is the inspection result normal?

Monitor item

Condition

BUCKLE SW 

When driver side seat belt is not fastened: ON

When driver side seat belt is fastened: OFF

(+)

(–)

Condition

Voltage (V)

(Approx.)

Seat belt buckle switch (driver side)

Connector

Terminal

B13*

1

1*

1

Ground

When driver side seat 
belt is fastened

8.5

When driver side seat 
belt is not fastened

0

B503*

2

61

*2

When driver side seat 
belt is fastened

8.5

When driver side seat 
belt is not fastened

0

Combination meter

Seat belt buckle switch (driver side)

Continuity

Connector

Terminal

Connector

Terminal

M53

29

B13*

1

1

*1

Existed

B503*

2

61*

2

Combination meter

Ground

Continuity

Connector

Terminal

M53

29

Not existed

SEAT BELT BUCKLE SWITCH (DRIVER SIDE)

SBC-39

< DTC/CIRCUIT DIAGNOSIS >

C

D

E

F

G

I

J

K

L

M

A

B

SBC

N

O

P

YES

>> Repair or replace combination meter.

NO

>> Repair or replace harness between combination meter and seat belt buckle switch (driver side).

3.

CHECK SEAT BELT BUCKLE SWITCH GROUND CIRCUIT

Check continuity between seat belt buckle switch (driver side) harness connector and ground.

*

1

: With climate controlled seat

*

2

: Without climate controlled seat

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace harness between seat belt buckle switch and ground.

4.

CHECK SEAT BELT BUCKLE SWITCH (DRIVER SIDE) 

Check seat belt buckle switch (driver side). Refer to 

SBC-39, "SEAT BELT WARNING LAMP SYSTEM : Com-

ponent Inspection (Belt Buckle Switch)"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace seat belt buckle switch (driver side).

SEAT BELT WARNING LAMP SYSTEM : Component Inspection (Belt Buckle Switch)

INFOID:0000000005241764

1.

CHECK SEAT BELT BUCKLE SWITCH (DRIVER SIDE)

1.

Turn ignition switch OFF

2.

Disconnect seat belt buckle switch connector.

3.

Check continuity of seat belt buckle (driver side).

*

1

: With climate controlled seat

*

2

: Without climate controlled seat

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace seat belt buckle switch (driver side).

Seat belt buckle switch (driver side)

Ground

Continuity

Connector

Terminal

B13*

1

2*

1

Existed

B503

*2

60

*2

Seat belt buckle switch (driver side)

Condition

Continuity

Connector

Terminal

B13

*1

1

2

When driver side seat 
belt is not fastened

Existed

When driver side seat 
belt is fastened

Not existed

B503*

2

61

60

When driver side seat 
belt is not fastened

Existed

When driver side seat 
belt is fastened

Not existed

SBC-40

< DTC/CIRCUIT DIAGNOSIS >

SEAT BELT BUCKLE SWITCH (PASSENGER SIDE)

SEAT BELT BUCKLE SWITCH (PASSENGER SIDE)

PRE-CRASH SEAT BELT SYSTEM

PRE-CRASH SEAT BELT SYSTEM : Description

INFOID:0000000005241765

• Performs the control of tension reducer according to the seat belt buckle switch ON/OFF.
• Detects whether or not the seat belt is fastened when the ignition switch turns ON. If the seat belt switch is

not fastened, illuminates the seat belt warning lamp on the combination meter.

• The seat belt buckle switch is installed in the seat belt buckle.

PRE-CRASH SEAT BELT SYSTEM : Component Function Check

INFOID:0000000005241766

1.

CHECK PRE-CRASH SEAT BELT CONTROL UNIT INPUT SIGNAL

 With CONSULT-III

When checking “BUCKLE SW RH” on DATA MONITOR screen, check that ON/OFF display changes are syn-
chronized with the insertion operation to the seat belt buckle.

Is the inspection result normal?

YES

>> Seat belt buckle switch (passenger side) circuit is normal.

NO

>> Refer to 

SBC-40, "PRE-CRASH SEAT BELT SYSTEM : Diagnosis Procedure"

.

PRE-CRASH SEAT BELT SYSTEM : Diagnosis Procedure

INFOID:0000000005241767

1.

CHECK PRE-CRASH SEAT BELT CONTROL UNIT INPUT SIGNAL

Check that voltage between seat belt buckle switch (passenger side) and ground.

Is the inspection result normal?

YES

>> Seat belt buckle switch (passenger side) circuit is normal.

NO

>> GO TO 2.

2.

CHECK SEAT BELT BUCKLE (PASSENGER SIDE) SWITCH CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect pre-crash seat belt control unit (passenger side) connector and seat belt buckle switch (pas-
senger side) connector.

3.

Check continuity between pre-crash seat belt control unit (passenger side) and seat belt buckle switch
(passenger side).

4.

Check continuity between pre-crash seat belt control unit (passenger side) and ground.

Monitor item

Condition

BUCKLE SW RH

When driver side seat belt is not fastened: OFF

When driver side seat belt is fastened: ON

(+)

(–)

Condition

Voltage (V)

(Approx.)

Seat belt buckle switch (passenger side)

Connector

Terminal

B513

59

Ground

When driver side seat 
belt is not fastened

5

When driver side seat 
belt is fastened

0

Pre-crash seat belt control unit (passenger side)

Seat belt buckle switch (passenger side)

Continuity

Connector

Terminal

Connector

Terminal

B221

6

B513

59

Existed

SEAT BELT BUCKLE SWITCH (PASSENGER SIDE)

SBC-41

< DTC/CIRCUIT DIAGNOSIS >

C

D

E

F

G

I

J

K

L

M

A

B

SBC

N

O

P

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace harness between pre-crash seat belt control unit (passenger side) and seat belt

buckle switch (passenger side).

3.

CHECK SEAT BELT BUCKLE SWITCH GROUND CIRCUIT

Check continuity between seat belt buckle switch (passenger side) and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace harness between seat belt buckle switch and ground.

4.

CHECK SEAT BELT BUCKLE SWITCH (PASSENGER SIDE) 

Check seat belt buckle switch (passenger side). Refer to 

SBC-41, "PRE-CRASH SEAT BELT SYSTEM : Com-

ponent Inspection (Belt Buckle Switch)"

.

Is the inspection result normal?

YES

>> Replace pre-crash seat belt control unit (passenger side).

NO

>> Replace seat belt buckle switch (passenger side).

PRE-CRASH SEAT BELT SYSTEM : Component Inspection (Belt Buckle Switch)

INFOID:0000000005241768

1.

CHECK SEAT BELT BUCKLE SWITCH (PASSENGER SIDE)

1.

Turn ignition switch OFF.

2.

Disconnect seat belt buckle switch connector.

3.

Check continuity of seat belt buckle (passenger side).

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace seat belt buckle switch (passenger side).

SEAT BELT WARNING LAMP SYSTEM

SEAT BELT WARNING LAMP SYSTEM : Description

INFOID:0000000005241769

• Performs the control of tension reducer according to the seat belt buckle switch ON/OFF.
• Detects whether or not the seat belt is fastened when the ignition switch turns ON. If the seat belt switch is

not fastened, illuminates the seat belt warning lamp on the combination meter.

• The seat belt buckle switch is installed in the seat belt buckle.

SEAT BELT WARNING LAMP SYSTEM : Component Function Check

INFOID:0000000005241770

1.

CHECK SEAT BELT WARNING FUNCTION

Pre-crash seat belt control unit (passenger side)

Ground

Continuity

Connector

Terminal

B221

6

Not existed

Seat belt buckle switch (passenger side)

Ground

Continuity

Connector

Terminal

B513

60

Existed

Seat belt buckle switch (passenger side)

Condition

Continuity

Terminal

59

60

When driver side seat belt is 
not fastened

Not existed

When driver side seat belt is 
fastened

Existed