Infiniti G37 Coupe. Manual - part 1076

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< FUNCTION DIAGNOSIS >

ON BOARD DIAGNOSTIC (OBD) SYSTEM

NOTE:
Timing display judges the status of self-diagnosis results judged from each input signal.
• When malfunction is found in the past and it is normal now, “MEMORY” is displayed.
• When malfunction is found at present or found immediately after the self-diagnosis, “CURRENT” is dis-

played.

• When malfunction is not found in the past and it is normal now, nothing is displayed.

CAUTION:

Some malfunctions are displayed at low battery voltage (when keeping 7 to 8 V for 2 seconds) even if
the system is not malfunctioning. Erase DTC memory and do not replace any parts after making sure
that the system is normal especially if the malfunctions are displayed after replacing battery.

DATA MONITOR

• Check DATA MONITOR

Diagnostic item

Malfunction judgement criteria

Refer to

CAN COMM CIRC [U1000]

CAN communication is malfunctioning.

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Seat belt motor system RH [B2451]

Circuit of seat belt motor (RH) is open or shorted.

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Seat belt motor system LH [B2452]

Circuit of seat belt motor (LH) is open or shorted.

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B-pedal sensor system [B2453]

Circuit of brake pedal stroke sensor is open or shorted.

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Motor power supply circuit system [B2454]

Circuit of motor power supply is open or shorted.

CAUTION:

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

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Monitor item

[Operation or unit]

Display item

B-pedal sensor SIG1

[V]

Brake pedal stroke sensor 1 signal voltage is displayed.

B-pedal sensor SIG2

[V]

Brake pedal stroke sensor 2 signal voltage is displayed.

BUCKLE SW RH

[ON/OFF]

ON/OFF status of RH seat belt switch signal is displayed.

BUCKLE SW LH

[ON/OFF]

ON/OFF status of LH seat belt switch signal is displayed.

Vehicle speed sensor

[km/h]

Vehicle speed signal is displayed.

U1000 CAN COMM CIRCUIT

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< COMPONENT DIAGNOSIS >

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COMPONENT DIAGNOSIS

U1000 CAN COMM CIRCUIT

Description

INFOID:0000000001711974

• CAN (Controller Area Network) is a serial communication line for real time applications. It is an on board

multiplex communication line with high data communication speed and excellent error detection ability.  A
modern vehicle is equipped with many ECMs, and each control unit shares information and links with other
control units during operation (not independent).  In CAN communication, two control units are connected
with two communication lines (CAN H-line, CAN L-line) allowing a high rate of information transmission with
less wiring. Each control unit transmits/receives data but selectively reads required data only.

• It transmits the vehicle status to pre-crash seat belt control unit using the CAN communication system.
• It consists of CAN system (unified meter and A/C amp). 
• Refer to 

LAN-25, "CAN System Specification Chart"

 in LAN section for CAN communication unit (2WD).

DTC Logic

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DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT

Check “SELF-DIAG RESULT” of CONSULT

−

lll.

Is any DTC detected?

YES

>> Refer to 

LAN-25, "CAN System Specification Chart"

 in LAN section for CAN communication or

CAN system.

NO

>> CAN communication system is normal.

DTC No.

Self-diagnosis 

item

DTC Detection Condition

Possible causes

U1000

CAN communi-

cation circuit

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

CAN message reception 
malfunction 

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< COMPONENT DIAGNOSIS >

B2451 SB MOTOR RH CIRC

B2451 SB MOTOR RH CIRC

Description

INFOID:0000000001711976

• It pulls, returns, and maintains according to the motor rotation.
• It is built into the seat belt retractor.
• It is installed to back of RH center pillar garnish.

DTC Logic

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DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

CHECK RH PRE-CRASH SEAT BELT MOTOR CIRCUIT

Check “SELF-DIAG RESULT” of CONSULT-lll.

Is any DTC detected?

YES

>> Refer to 

SBC-14, "Diagnosis Procedure"

.

NO

>> RH pre-crash seat belt motor system is normal.

Diagnosis Procedure

INFOID:0000000001711978

1.

CHECK RH PRE-CRASH SEAT BELT MOTOR HARNESS

1.

Turn the ignition switch OFF.

2.

Disconnect pre-crash seat belt control unit and RH pre-crash seat belt motor connector.

3.

Does continuity between pre-crash seat belt control unit harness connector terminals 1, 3 and RH pre-
crash seat belt motor harness connector terminals 1, 2 exist?

4.

Does continuity between pre-crash seat belt control unit harness connector terminals 1, 3 and ground
exist?

Is the inspection result normal?

YES

>> Refer to 

SBC-14, "Component Inspection"

.

NO

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

motor.

Component Inspection

INFOID:0000000001711979

COMPONENT PARTS INSPECTION

1.

CHECK RH PRE-CRASH SEAT BELT MOTOR

Does continuity between RH pre-crash seat belt motor terminals 1 and 2 exist?

Is the inspection result normal?

DTC No.

Self-diagnosis item

DTC Detection Condition

Possible causes

B2451

Seat belt motor system 
RH

Circuit of seat belt motor (RH) is open or 
shorted

• Open circuit, short circuit to battery, and 

short circuit to ground in seat belt motor 
(RH) harness 

• ECU internal malfunction 

1 - 1

Existed

2 - 3

Existed

1 - Ground

Not existed

3 - Ground

Not existed

1 - 2

Existed

B2451 SB MOTOR RH CIRC

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< COMPONENT DIAGNOSIS >

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YES

>> Replace pre-crash seat belt control unit.

NO

>> Replace RH pre-crash seat belt motor.