2011 INFINITI QX56 ABS

SYSTEMSBC-9
< SYSTEM DESCRIPTION >
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PRE-CRASH SEAT BELT SYSTEM : Fail SafeINFOID:0000000006237879
 When a system malfunction is detected, deactivates a part of the system or all functions depending on the
malfunctioning part.
 When the malfunction condition recovers to the norma l condition, the system returns to the normal opera-
tion.
*1: The deactivation mode differs depending on the internal malfunctioning condition of control unit Display contents of CONSULT-III Fail-safe
U0126 STRG ANG SEN SIG Stops the operation in the conditions as per the following.
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 A part of comfort function
U0428 STRG ANGL CAL Stops the operation in the conditions as per the following.
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 A part of comfort function
U1000 CAN communication circuit Stops the operation in the conditions as per the following. *
1
 During emergency brake operation
 When ABS continuously operates
 When lateral slippage during cornering occurs
 When Intelligent brake assistance operates
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2451 SEAT BLT MTR DR CIRC Fully deactivates the whole operation.
B2452 SEAT BLT MTR AS CIRC Deactivate s a part of comfort function.
B2453 BR_STROKE_SEN_CIRC Stops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuously operates
 A part of comfort function
B2454 SEAT BLT PWR DR CIRC Fully deactivates the whole operation.
B2455 CONTROL UNIT DR Stops the operation in the conditions as per the following. *
1
 During emergency brake operation
 When ABS continuously operates
 When lateral slippage during cornering occurs
 When Intelligent brake assistance operates
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2456 SEAT BLT PWR AS Deactivates a part of comfort function.
B2457 CONTROL UNIT AS Deactivates a part of comfort function.
B2458 LOCAL COMM Deactivates a part of comfort function.
B2461 VHCL SPEED SIGNAL Stops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuously operates
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 When comfort function operates
B2463 ROLLOVER SIGNAL Stops the operation in the conditions as per the following.
 When the vehicle inclined excessively
 A part or the whole comfort function
B2466 DR/AS CONTROL UNIT Deactivates a part of comfort function.
B2470 SYS HEAT PROTC DR  Fully deactivates the whole operation.
 Operation return
- 1 time operation becomes possible after approximately 30 seconds
- Returns to the initial condition after approximately 8 minutes
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (PRE-CRASH SEAT BELT)SBC-11
< SYSTEM DESCRIPTION >
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DIAGNOSIS SYSTEM (P RE-CRASH SEAT BELT)
CONSULT-III FunctionINFOID:0000000006237882
Diagnosis for pre-crash seat belt syst em can be performed using CONSULT-III.
APPLICATION ITEM
SELF-DIAGNOSIS RESULTS
Refer to SBC-16, "DTC Index".
CAUTION:
When malfunctions are detect ed in several systems, includin g CAN communication [U1000], trouble-
shoot CAN communication [U1000].
A malfunction of system may be disp layed when battery voltage is low (when 7 to 8 V is continued for
approximately 2 seconds) even though the system is not malfunctioning. Erase DTC memory and
never replace any parts after making sure that the syst em is normal, especially if the malfunctions are
displayed after replacing battery.
ERASING SELF-DIAGNOSIS RESULTS
 SELF-DIAGNOSIS RESULTS Current “SELF-DIAG RESULTS” are displayed. (If all suspect circuits have been repaired, “NO DTC” is dis-
played.)
DATA MONITOR
Part to be diagnosed Diagnosis Mode Function description
Pre-crash seat belt Self-diagnosis Results
 Displays data recorded when a malfunction is de-
tected.
 Erases DTC recorded in memory.
Data Monitor Displays input data for pre-crash seat belt control
unit in real time.
Work Support Changes the setting for each system function.
CAN DIAG SUPPORT MNTR Monitors communication status of CAN communi-
cation.
Ecu Identification Displays pre-crash seat belt control unit part num-
ber.
Monitor item Contents
BUCKLE SW RH Indicates [ON/OFF] condition of seat belt buckle switch (RH).
BUCKLE SW LH Indicates [ON/OFF] condition of seat belt buckle switch (LH).
VEHICLE DISTANCE Indicates [ON/OFF] condit ion of intelligent brake assist signal.
IGN SW Indicates [ON/OFF] condition of ignition switch.
FR DOOR SW RH Indicates [Close/Open] condition of front door switch (RH).
FR DOOR SW LH Indicates [Close/Open] condition of front door switch (LH).
ABS ACTIVATING Indicates [ON/OFF] co ndition of ABS operation signal.
VHCL SPEED Indicates [Km/h] vehicle speed signal.
BRK PEDAL SNSR1 Indicates [V] voltage of brake pedal stroke sensor 1 signal.
BRK PEDAL SNSR2 Indicates [V] voltage of brake pedal stroke sensor 2 signal.
STRG ANGLE Indicates [deg] steering angle signal.
STRG ANGLE SPEED Indicates [deg/s] steering angle speed signal.
INCLINATION JDMT Indicates [ON/OFF] condition of pre roll over signal.
PRE-TEN ACTIVTN Indicates [ON/OFF] condition of pre-tensioner operated signal.
HEAT PROTC RH Indicates [ON/OFF] condition of heat protection (RH).
HEAT PROTC LH Indicates [ON/OFF] condition of heat protection (LH).
Revision: 2010 May2011 QX56

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

PRE-CRASH SEAT BELT CONTROL UNIT (DRIVER SIDE)SBC-15
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*1: The deactivation mode differs depending on the internal malfunctioning condition of control unit Display contents of CONSULT-III Fail-safe
U0126 STRG ANG SEN SIG Stops the operation in the conditions as per the following.
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 A part of comfort function
U0428 STRG ANGL CAL Stops the operation in the conditions as per the following.
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 A part of comfort function
U1000 CAN communication circuit Stops the operation in the conditions as per the following. *
1
 During emergency brake operation
 When ABS continuously operates
 When lateral slippage during cornering occurs
 When Intelligent brake assistance operates
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2451 SEAT BLT MTR DR CIRC Fully deactivates the whole operation.
B2452 SEAT BLT MTR AS CIRC Deactivate s a part of comfort function.
B2453 BR_STROKE_SEN_CIRC Stops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuously operates
 A part of comfort function
B2454 SEAT BLT PWR DR CIRC Fully deactivates the whole operation.
B2455 CONTROL UNIT DR Stops the operation in the conditions as per the following. *
1
 During emergency brake operation
 When ABS continuously operates
 When lateral slippage during cornering occurs
 When Intelligent brake assistance operates
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2456 SEAT BLT PWR AS Deactivates a part of comfort function.
B2457 CONTROL UNIT AS Deactivates a part of comfort function.
B2458 LOCAL COMM Deactivates a part of comfort function.
B2461 VHCL SPEED SIGNAL Stops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuously operates
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 When comfort function operates
B2463 ROLLOVER SIGNAL Stops the operation in the conditions as per the following.
 When the vehicle inclined excessively
 A part or the whole comfort function
B2466 DR/AS CONTROL UNIT Deactivates a part of comfort function.
B2470 SYS HEAT PROTC DR  Fully deactivates the whole operation.
 Operation return
- 1 time operation becomes possible after approximately 30 seconds
- Returns to the initial condition after approximately 8 minutes
Revision: 2010 May2011 QX56

SBC-18
< ECU DIAGNOSIS INFORMATION >
PRE-CRASH SEAT BELT CONTROL UNIT (PASSENGER SIDE)
*1: The deactivation mode differs depending on the internal malfunctioning condition of control unit
U1000 CAN communication circuit
Stops the operation in the conditions as per the following. *
1
 During emergency brake operation
 When ABS continuo
usly operates
 When lateral slippage during cornering occurs
 When Intelligent brake assistance operates
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2452 SEAT BLT MTR AS CIRC Fully deactivates the whole operation.
B2453 BR_STROKE_SEN_CIRC Stops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuo
usly operates
B2455 CONTROL UNIT DR Stops the operation in the conditions as per the following. *
1
 During emergency brake operation
 When ABS continuo
usly operates
 When lateral slippage during cornering occurs
 When Intelligent brake assistance operates
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2456 SEAT BLT PWR AS Fully deactivates the whole operation.
B2457 CONTROL UNIT AS Fully deactivates the whole operation.*
1
B2458 LOCAL COMM
Fully deactivates the whole operation.*1
B2461 VHCL SPEED SIGNALStops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuo
usly operates
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2463 ROLLOVER SIGNAL When the vehicle inclined excessively
B2466 DR/AS CONTROL UNIT Stops the operation in the conditions as per the following.
 During emergency brake operation
 When ABS continuo
usly operates
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
 When the vehicle inclined excessively
 A part or the whole comfort function
B2471 SYS HEAT PROTC AS  Fully deactivates the whole operation.
 Operation return
- 1 time operation becomes possible after approximately 30 seconds
- Returns to the initial condition after approximately 8 minutes
Display contents of CONSULT-III Fail-safe
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

SCS-1
SUSPENSION
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SUSPENSION CONTROL SYSTEM
HBMC
PRECAUTION ................ ...............................
4
PRECAUTIONS .............................................. .....4
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
4
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
4
Precaution for Procedure without Cowl Top Cover ......5
Precaution for Hydraulic Body-Motion Control
System ......................................................................
5
PREPARATION ............................................6
PREPARATION .............................................. .....6
Special Service Tools .......................................... ......6
Commercial Service Tools ........................................6
SYSTEM DESCRIPTION ..............................7
DESCRIPTION ............................................... .....7
Description .......................................................... ......7
COMPONENT PARTS ........................................8
Component Parts Location .................................. ......8
Component Description .............................................8
STRUCTURE AND OPERATION ........................9
Hydraulic Body-Motion Control System .............. ......9
Shock Absorber .........................................................9
PPMU ......................................................................10
Accumulator ............................................................11
PPMU Pipe ..............................................................11
SYSTEM .............................................................12
System Diagram .................................................. ....12
System Description .................................................12
Component Description ...........................................14
BASIC INSPECTION ...................................15
CHECK SYSTEM PRESSURE .........................15
Work Procedure ................................................... ....15
PRESSURE REDUCING METHOD ..................17
Work Procedure .......................................................17
AIR BLEEDING METHOD ................................18
Work Procedure .......................................................18
CHECK INTERNAL LEAKAGE ........................20
Work Procedure .......................................................20
CHECK FOR MALFUNCTION ..........................22
Work Procedure .......................................................22
CHECK SHOCK ABSORBER FOR MAL-
FUNCTION ....................................... .................
24
Work Procedure ................................................... ....24
CHECK ORIFICE FOR CLOGGING .................27
Work Procedure .......................................................27
SYMPTOM DIAGNOSIS ..............................29
DIFFERENCE IN APPEARANCE .....................29
Description ........................................................... ....29
Inspection Procedure ...............................................29
LARGE ROLL ANGLE ......................................30
Description ...............................................................30
Inspection Procedure ...............................................30
REMOVAL AND INSTALLATION ...............31
HYDRAULIC BODY-MOTION CONTROL
SYSTEM ............................................................
31
Hydraulic Piping ................................................... ....31
FRONT TUBE ASSEMBLY .......................................31
FRONT TUBE ASSEMBLY : Exploded View ...... ....32
FRONT TUBE ASSEMBLY : Removal and Instal-
lation ........................................................................
32
FRONT TUBE ASSEMBLY : Inspection ..................34
Revision: 2010 May2011 QX56