2011 INFINITI QX56 ignition

PRE-CRASH SEAT BELT CONTROL UNIT (DRIVER SIDE)SBC-13
< ECU DIAGNOSIS INFORMATION >
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ECU DIAGNOSIS INFORMATION
PRE-CRASH SEAT BELT CONTROL UNIT (DRIVER SIDE)
Reference ValueINFOID:0000000006237883
VALUES ON THE DIAGNOSIS TOOL
CONSULT-III MONITOR ITEM
Monitor item Condition Value/Status
(Approx.)
BUCKLE SW RH RH seat belt is not fastened OFF
RH seat belt is fastened ON
BUCKLE SW LH RH seat belt is not fastened OFF
RH seat belt is fastened ON
VEHICLE DISTANCE Not activated OFF
Activated ON
IGN SW Ignition switch OFF OFF
Ignition switch ON ON
FR DOOR SW RH LH door close CLOSE
LH door open OPEN
FR DOOR SW LH RH door close CLOSE
RH door open OPEN
ABS ACTIVATING ABS is inactive OFF
ABS is active ON
VHCL SPEED While driving Equival ent speedometer reading (km/h)
BRK PEDAL SNSR1 Brake released → depressed (1 V → 4 V)
BRK PEDAL SNSR2 Brake released → depressed (4 V → 1 V)
STRG ANGLE Steering wheel: 0
° (Neutral) ±2.5 (deg)
Steering wheel: 90 ° (Turned right) +90 (deg)
Steering wheel: 90 ° (Turned left) -90 (deg)
STRG ANGLE SPEED Steering wheel: Being turnedDepending on steering acceleration speed
(deg/s)
INCLINATION JDMT Vehicle is level OFF
Vehicle is inclined ON
PRE-TEN ACTIVTN Seat belt pre-tensioner is not activated OFF
Seat belt pre-tensioner is activated ON
HEAT PROTC RH RH heat protection is not activated OFF
RH heat protection is activated ON
HEAT PROTC LH LH heat protection is not activated OFF
LH heat protection is activated ON
Revision: 2010 May2011 QX56

U0126 ST ANG SEN SIGSBC-33
< DTC/CIRCUIT DIAGNOSIS >
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DTC/CIRCUIT DIAGNOSIS
U0126 ST ANG SEN SIG
DescriptionINFOID:0000000006237891
Inputs the steering angle signal from steering angle sensor via CAN communication.
DTC LogicINFOID:0000000006237892
DTC DETECTION LOGIC
NOTE:
If DTC U0126 is displayed with DTC U1000, first per form the trouble diagnosis for DTC U1000. Refer to SBC-
35, "DTC Logic".
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-33, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237893
1.CHECK DTC WITH “ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)”
Check “Self-diagnostic result” for “ABS” with CONSULT-III. Refer to BRC-40, "
CONSULT-III Function".
Is DTC detected?
YES >> Repair or replace malfunctioning parts.
NO >> GO TO 2.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
U0126 ST ANG SEN SIG Receipt of a malfunction signal of Steering angle signal Steering angle sensor
Revision: 2010 May2011 QX56

SBC-34
< DTC/CIRCUIT DIAGNOSIS >
U0428 STRG ANGL CAL
U0428 STRG ANGL CAL
DescriptionINFOID:0000000006237894
Inputs the steering calibration incomplete signal from steering angle sensor via CAN communication.
DTC LogicINFOID:0000000006237895
DTC DETECTION LOGIC
NOTE:
If DTC U0428 is displayed with DTC U0126, first perform the trouble diagnosis for DTC U0126. Refer to SBC-
33, "DTC Logic".
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-34, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237896
1.CHECK DTC WITH “ABS ACTUATOR A ND ELECTRIC UNIT (CONTROL UNIT)”
Check “Self-diagnostic result” for “ABS” with CONSULT-III. Refer to BRC-40, "
CONSULT-III Function".
Is DTC detected?
YES >> Repair or replace malfunctioning parts.
NO >> GO TO 2.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
U0428 STRG ANGL CAL Receipt of the calibration incomplete signal Steering angle sensor calibration incomplete
Revision: 2010 May2011 QX56

U1000 CAN COMM CIRCUITSBC-35
< DTC/CIRCUIT DIAGNOSIS >
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U1000 CAN COMM CIRCUIT
DescriptionINFOID:0000000006237897
 CAN (Controller Area Network) is a serial communica tion 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 cont rol unit shares information and links with other
control units during operation (not independent). In CA N 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/receive s 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., ICC sensor, BCM, steering angle sensor).
 Refer to LAN-27, "
CAN COMMUNICATION SYSTEM : CA N System Specification Chart".
DTC LogicINFOID:0000000006237898
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON and wait for 2 seconds or more.
2. Check “Self-diagnostic result” with CONSULT-III.
Is any DTC detected?
YES >> Refer to LAN-27, "CAN COMMUNICATION SYSTEM : CA N System Specification Chart".
NO >> CAN communication system is normal.
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
U1000 CAN communication
circuit Pre-crash seat belt control unit cannot transmit and re-
ceive CAN communication system for 2 seconds or
more.  Harness or connectors
(CAN communication line is open
or shorted)
Revision: 2010 May2011 QX56

SBC-36
< DTC/CIRCUIT DIAGNOSIS >
B2451 SEAT BLT MTR DR CIRC
B2451 SEAT BLT MTR DR CIRC
DTC LogicINFOID:0000000006237899
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-36, "Diagnosis Procedure".
NO >> Driver side pre-crash seat belt motor system is normal.
Diagnosis ProcedureINFOID:0000000006237900
1.INSPECTION START
1. Check “Self-diagnostic result” with CONSULT-III.
2. Touch “ERASE”.
3. Perform DTC Confirmation Procedure. Refer to SBC-36, "
DTC Logic".
Is DTC B2451 displayed again?
YES >> Replace pre-crash seat belt control unit (driver side). Refer to SB-6, "SEAT BELT RETRACTOR :
Removal and Installation".
NO >> GO TO 2.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
B2451 SEAT BLT MTR DR CIRC Circuit of seat belt
motor (driver side) is
open or shorted Pre-crash seat belt control unit (driver side)
Revision: 2010 May2011 QX56

B2452 SEAT BLT MTR AS CIRCSBC-37
< DTC/CIRCUIT DIAGNOSIS >
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B2452 SEAT BLT MTR AS CIRC
DTC LogicINFOID:0000000006237901
DTC DETECTION LOGIC
DTC REPRODUCTION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-37, "Diagnosis Procedure".
NO >> Passenger side pre-crash seat belt motor system is normal.
Diagnosis ProcedureINFOID:0000000006237902
1.INSPECTION START
1. Check “Self-diagnostic result” with CONSULT-III.
2. Touch “ERASE”.
3. Perform DTC Confirmation Procedure. Refer to SBC-37, "
DTC Logic".
Is DTC B2452 displayed again?
YES >> Replace pre-crash seat belt control unit (passenger side). Refer to SB-6, "SEAT BELT RETRAC-
TOR : Removal and Installation".
NO >> GO TO 2.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
B2452 SEAT BLT MTR AS CIRC Circuit of seat belt motor (passenger side)
is open or shorted Pre-crash seat belt control unit (passenger
side)
Revision: 2010 May2011 QX56

SBC-38
< DTC/CIRCUIT DIAGNOSIS >
B2453 BR STROKE SEN CIRC
B2453 BR STROKE SEN CIRC
DTC LogicINFOID:0000000006237903
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-38, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237904
1.CHECK PRE-CRASH SEAT BELT CONTROL UNIT INPUT SIGNAL
1. Turn ignition switch ON.
2. Select “BRK PEDAL SNSR1” and “BRK PEDAL SNSR2” in “DATA MONITOR” mode with CONSULT-III.
3. Check “BRK PEDAL SNSR1” and “BRK PEDAL SNSR2” indication under the following conditions.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK BRAKE PEDAL STROKE SENSOR POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect brake pedal stroke sensor harness connector.
3. Check voltage between brake pedal stroke sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK BRAKE PEDAL STROKE SENSOR POWER SUPPLY CIRCUIT
1. Disconnect pre-crash seat belt contro l unit (driver side) harness connector.
2. Check continuity between pre-crash seat belt c ontrol unit (driver side) harness connector and brake pedal
stroke sensor harness connector.
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
B2453 BR STROKE SEN CIRC Circuit of brake pedal stroke sensor out-
put is open or shorted  Harness or connectors
(The sensor circuit is open or shorted)
 Pre-crash seat belt co ntrol unit (driver side)
 Brake pedal stroke sensor
Monitor item Condition Voltage (V)
(Approx.)
BRK PEDAL SNSR1 Brake released → depressed 1
→ 4
BRK PEDAL SNSR2 4 → 1
Brake pedal stroke sensor
GroundVoltage (V)
(Approx.)
Connector Terminal
E 111 2 5
Pre-crash seat belt control unit (driver side) Brake pedal stroke sensor Continuity
Connector Terminal Connector Terminal
B9 10 E111 2 Existed
Revision: 2010 May2011 QX56

B2453 BR STROKE SEN CIRCSBC-39
< DTC/CIRCUIT DIAGNOSIS >
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3. Check continuity between pre-crash seat belt control unit (driver side) harness connector and ground.
Is the inspection result normal?
YES >> Replace pre-crash seat belt c ontrol unit (driver side). Refer to SB-6, "SEAT BELT RETRACTOR :
Removal and Installation".
NO >> Repair or replace harness or connector.
4.CHECK BRAKE PEDAL STROKE SENSOR CIRCUIT
1. Disconnect pre-crash seat belt control unit (driver side) harness connector.
2. Check continuity between pre-crash seat belt c ontrol unit (driver side) harness connector and brake pedal
stroke sensor harness connector.
3. Check continuity between pre-crash seat belt control unit harness connector (driver side) and ground.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace harness or connector.
5.CHECK BRAKE PEDAL STROKE SENSOR
Refer to SBC-39, "
Component Inspection".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Replace brake pedal stroke sensor. Refer to SBC-63, "
Removal and Installation".
6.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000006237905
COMPONENT PARTS INSPECTION
1.CHECK BRAKE PEDAL STROKE SENSOR
1. Turn ignition switch OFF.
2. Disconnect brake pedal stroke sensor connector.
3. Check resistance between brake pedal stroke sensor terminal as per the following.
Pre-crash seat belt control unit (driver side)
GroundContinuity
Connector Terminal
B9 10 Not existed
Pre-crash seat belt control unit (driver side) Brake pedal stroke sensor Continuity
Connector Terminal Connector Terminal
B9 2
E 111 1
Existed
12 3
17 4
Pre-crash seat belt control unit (driver side) GroundContinuity
Connector Terminal
B9 2
Not existed
12
17
Revision: 2010 May2011 QX56