Infiniti G37 Coupe. Manual - part 1080

SBC-28

< COMPONENT DIAGNOSIS >

PRE-CRASH SEAT BELT CONTROL UNIT GROUND CIRCUIT CHECK

PRE-CRASH SEAT BELT CONTROL UNIT GROUND CIRCUIT CHECK

Description

INFOID:0000000001712005

• The pre-crash seat belt control unit controls the pre-crash seat belt motor according to the input signal.
• When the control unit judges the emergency braking operation and the intelligent brake assistance operating

status, it gives the sense of security by the motor built into the pre-crash seat belt motor retracting the shoul-
der belt and suppressing the crew's posture change. Or, it eases the damage of the collision.

• It is installed on the back of the glove box.

Component Function Check

INFOID:0000000001712006

1.

CHECK PRE-CRASH SEAT BELT CONTROL UNIT GROUND CIRCUIT

1.

Turn the ignition switch OFF.

2.

Disconnect the pre-crash seat belt control unit connector.

3.

Check that continuity between pre-crash seat belt control unit harness connector terminals 5, 26 and
ground is normal.

Is the inspection result normal?

YES

>> Ground system is normal.

NO

>> Repair or replace harness between pre-crash seat belt control unit and ground.

5 - Ground

Existed

26 - Ground

Existed

PRE-CRASH SEAT BELT CONTROL UNIT

SBC-29

< ECU DIAGNOSIS >

C

D

E

F

G

I

J

K

L

M

A

B

SBC

N

O

P

ECU DIAGNOSIS

PRE-CRASH SEAT BELT CONTROL UNIT

Reference Value

INFOID:0000000001712010

VALUES ON THE DIAGNOSIS TOOL

CONSULT-III MONITOR ITEM

TERMINAL LAYOUT

PHYSICAL VALUES

Monitor item

Condition

Value/Status

(Approx)

B PEDAL SENS SIG1
B PEDAL SENS SIG2

Brake released
Brake released

(1V)
(4V)

B PEDAL SENS SIG1
B PEDAL SENS SIG2

Brake released 

→

 depressed

Brake released 

→

 depressed

(1V

→

4V)

(4V

→

1V)

RH BUCKLE SW

RH seat belt is not fastened
RH seat belt is fastened

OFF
ON

LH BUCKLE SW

LH seat belt is not fastened
LH seat belt is fastened

OFF
ON

JMHIA0181ZZ

Terminal No.

Wire col-

or

Description

Condition

Value (*1)

(Approx)

+

–

Signal name

Input/

Output

1

GND

G/R

RH seat belt motor release signal

Output

—

—

2

GND

W

Drive circuit power supply (+BAT)

Input

Seat belt motor non-operational

BAT

3

GND

G/Y

RH seat belt motor forward (retract) 
signal

Output

—

—

4

GND

GR/W

LH seat belt motor forward (retract) 
signal

Output

—

—

5

GND

W

Drive circuit ground

—

Always

GND

6

GND

LY

LH seat belt motor release signal

Output

—

—

7

GND

G

Indicator (seat belt warning lamp)

Output

LH seat belt is not fastened

GND

LH seat belt is fastened

BAT

LH seat belt is fastened or malfunc-
tion of system

BAT

←→

GND

(0.5sec) 

8

GND

LG

RH seat belt buckle switch signal

Input

RH seat belt is fastened

BAT

RH seat belt is not fastened

GND

10

GND

SB

LH seat belt buckle switch signal

Input

LH seat belt is fastened

OPEN

LH seat belt is not fastened

GND

SBC-30

< ECU DIAGNOSIS >

PRE-CRASH SEAT BELT CONTROL UNIT

*1: Perform the measurement while connecting the control unit and the harness.
*2: The value may be changed according to the brake pedal depressed amount.

Fail Safe

INFOID:0000000001712011

When a malfunction occurs in the following system, the pre-crash seat belt function is controlled according to
the malfunctioning parts.

DTC Index

INFOID:0000000001712012

DISPLAY ITEM LIST (PRE-CRASH SEAT BELT)

13

GND

W

Control circuit power supply (IGN)

Input

IGN ON

BAT

IGN OFF

GND

16

GND

W

Brake pedal stroke sensor signal1

Input

IGN ON

(1

→

4V) *2

IGN OFF

0V

18

GND

R

Brake pedal stroke sensor power cir-
cuit

Output

IGN ON

5V

IGN OFF

0V

20

GND

G

Brake pedal stroke sensor signal2

Input

IGN ON

(4

→

1V)  *2

IGN OFF

0V

21

GND

B

Brake pedal stroke sensor ground  
circuit

—

Always

GND

22

GND

P

CAN communication signal (CAN L-
line)

Input/

Output

—

—

24

GND

L

CAN communication signal (CAN H-
line)

Input/

Output

—

—

25

GND

SHIELD

Shield ground

—

Always

GND

26

GND

B

Control circuit ground 

—

Always

GND

Terminal No.

Wire col-

or

Description

Condition

Value (*1)

(Approx)

+

–

Signal name

Input/

Output

Display contents of CONSULT-III

Fail-safe

Cancellation

B2451: SB MOTOR RH CIRC 

Deactivate the RH pre-crash seat belt function 

Erase DTC

B2452: SB MOTOR LH CIRC

Deactivate the LH pre-crash seat belt function 

Erace DTC

B2453: BR STROK SEN CIRC 

Deactivate the interlock function during emergency 
brake operation 

Erace DTC

B2454: MOTOR PWR SUP CIRC

Deactivate the pre-crash seat belt function 

Erace DTC

DTC

Trouble diagnosis name

(CONSULT-III display)

DTC detection condition

Reference

—

—

No malfunction is detected

—

U1000

CAN COMM CIRCUIT

Pre-crash seat belt control unit cannot transmit and receive CAN 
communication signal for 2 seconds or more

SBC-13

B2451

SB MOTOR RH CIRC

RH seat belt motor circuit is shorted or open

SBC-14

B2452

SB MOTOR LH CIRC

LH seat belt motor circuit is shorted or open

SBC-16

B2453

BR STROK SEN CIRC

Brake pedal stroke sensor circuit is shorted or open

SBC-18

B2454

MOTOR PWR SUP CIRC

Motor power supply circuit is shorted or open

CAUTION:

Malfunction is judged when 30A (F/L-G) fusible link blows out 
even if motor power supply circuit is not malfunctioning. 

SBC-20

B2455

PSB C/U INT CIRCUIT

Internal breakdown in pre-crash seat belt control unit

SBC-21

PRE-CRASH SEAT BELT CONTROL UNIT

SBC-31

< ECU DIAGNOSIS >

C

D

E

F

G

I

J

K

L

M

A

B

SBC

N

O

P

Wiring Diagram - SEAT BELT CONTROL SYSTEM -

INFOID:0000000001712013

JCHWA0096GB