2011 INFINITI QX56 engine

BRC-2
ADDITIONAL SERVICE WHEN REPLACING
ABS ACTUATOR AND ELECTRIC UNIT
(CONTROL UNIT) ..............................................
63
Description ........................................................... ...63
ADJUSTMENT OF STEERING ANGLE SEN-
SOR NEUTRAL POSITION ...............................
64
Description ........................................................... ...64
Work Procedure ......................................................64
CALIBRATION OF DECEL G SENSOR ...........66
Description ........................................................... ...66
Work Procedure ......................................................66
DTC/CIRCUIT DIAGNOSIS ...................... ...68
C1101, C1102, C1103, C1104 WHEEL SEN-
SOR ................................................................. ...
68
DTC Logic ............................................................ ...68
Diagnosis Procedure ..............................................68
C1105, C1106, C1107, C1108 WHEEL SEN-
SOR ....................................................................
70
DTC Logic ............................................................ ...70
Diagnosis Procedure ..............................................70
C1109 POWER AND GROUND SYSTEM .........72
Description ........................................................... ...72
DTC Logic ...............................................................72
Diagnosis Procedure ..............................................72
C1111 PUMP MOTOR .......................................75
DTC Logic ............................................................ ...75
Diagnosis Procedure ..............................................75
C1115 WHEEL SENSOR ...................................77
DTC Logic ............................................................ ...77
Diagnosis Procedure ..............................................77
C1116 STOP LAMP SWITCH ............................79
DTC Logic ............................................................ ...79
Diagnosis Procedure ..............................................79
Component Inspection (Stop lamp Switch) ............85
Component Inspection (Stop Lamp Relay) .............86
C1118 TRANSFER CONTROL UNIT ................87
DTC Logic ............................................................ ...87
Diagnosis Procedure ..............................................87
C1120, C1122, C1124, C1126 ABS IN VALVE
SYSTEM .......................................................... ...
88
DTC Logic ............................................................ ...88
Diagnosis Procedure ..............................................88
C1121, C1123, C1125, C1127 ABS OUT
VALVE SYSTEM ................................................
90
DTC Logic ............................................................ ...90
Diagnosis Procedure ..............................................90
C1130 ENGINE SIGNAL ...................................92
DTC Logic ............................................................ ...92
Diagnosis Procedure ............................................ ...92
C1140 ACTUATOR RELAY SYSTEM ..............93
DTC Logic ............................................................ ...93
Diagnosis Procedure ...............................................93
C1142 PRESS SENSOR ...................................95
DTC Logic ............................................................ ...95
Diagnosis Procedure ...............................................95
C1143 STEERING ANGLE SENSOR ...............97
DTC Logic ............................................................ ...97
Diagnosis Procedure ...............................................97
C1144 INCOMPLETE STEERING ANGLE
SENSOR ADJUSTMENT ..................................
99
DTC Logic ............................................................ ...99
Diagnosis Procedure ...............................................99
C1145, C1146 YAW RATE/SIDE/DECEL G
SENSOR ...........................................................
100
DTC Logic ............................................................ .100
Diagnosis Procedure .............................................100
C1155 BRAKE FLUID LEVEL SWITCH ..........103
DTC Logic ............................................................ .103
Diagnosis Procedure .............................................103
Component Inspection ..........................................104
C1160 DECEL G SEN SET ..............................105
DTC Logic ............................................................ .105
Diagnosis Procedure .............................................105
C1164, C1165 CV SYSTEM .............................106
DTC Logic ............................................................ .106
Diagnosis Procedure .............................................106
C1166, C1167 SV SYSTEM .............................108
DTC Logic ............................................................ .108
Diagnosis Procedure .............................................108
C1170 VARIANT CODING ...............................110
DTC Logic ............................................................ .110
Diagnosis Procedure .............................................110
C118E ACCUMULATOR ..................................111
DTC Logic ............................................................ .111
Diagnosis Procedure .............................................111
U1000 CAN COMM CIRCUIT ...........................112
Description ........................................................... .112
DTC Logic .............................................................112
Diagnosis Procedure .............................................112
POWER SUPPLY AND GROUND CIRCUIT ....113
Description ........................................................... .113
Diagnosis Procedure .............................................113
PARKING BRAKE SWITCH .............................117
Component Function Check ................................ .117
Diagnosis Procedure .............................................117
Component Inspection ..........................................118
Revision: 2010 May2011 QX56

PRECAUTIONSBRC-5
< PRECAUTION > [WITH VDC]
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006228174
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision that would result in air ba g inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the
ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minutes before performing any service.
Precaution Necessary for Steering Wh eel Rotation after Battery Disconnect
INFOID:0000000006228175
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect both battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
For vehicle with steering lock unit, if the battery is disconnected or discharged, the steering wheel will lock and
cannot be turned.
If turning the steering wheel is required with the batte ry disconnected or discharged, follow the operation pro-
cedure below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wil l remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56

BRC-6
< PRECAUTION >[WITH VDC]
PRECAUTIONS
5. When the repair work is completed, re-connect bot
h battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button igniti on switch is turned to LOCK position.)
6. Perform self-diagnosis check of all control units using CONSULT-III.
Precaution for Procedure without Cowl Top CoverINFOID:0000000006228176
When performing the procedure after removing cowl top cover, cover
the lower end of windshield with urethane, etc.
Precaution for Brake SystemINFOID:0000000006222556
WARNING:
Clean any dust from the front brake and rear brake using a vacuum dust collector. Never blow by com-
pressed air.
 Brake fluid use refer to MA-10, "
Fluids and Lubricants".
 Never reuse drained brake fluid.
 Never spill or splash brake fluid on painted surfaces. Brake fluid may seriously damage paint. Wipe it off
immediately and wash with water if it gets on a painted surface.
 Always confirm the specified tightening torque when installing the brake pipes.
 After pressing the brake pedal more deeply or harder t han normal driving, such as air bleeding, check each
item of brake pedal. Adjust brake pedal if it is outside the standard value.
 Never use mineral oils such as gasoline or light oil to clean. They may damage rubber parts and cause
improper operation.
 Always loosen the brake tube flar e nut with a flare nut wrench.
 Tighten the brake tube flare nut to the specified torque with a crow-
foot (A) and torque wrench (B).
 Always connect the battery terminal when moving the vehicle.
 Turn the ignition switch OFF and disconnect the ABS actuator and
electric unit (control unit) harness connector or the battery negative
terminal before performing the work.
 Check that no brake fluid leakage is present after replacing the parts.
Precaution for Brak e Control SystemINFOID:0000000006222557
 Slight vibrations are felt on the brake pedal and the operation noises occur, when VDC function, TCS func-
tion, ABS function, EBD function, hill start assist function or brake limited slip differential (BLSD) function
operates. This is not a malfunction because it is caus ed by VDC function, TCS function, ABS function, EBD
function, hill start assist function or brake limited sl ip differential (BLSD) function that is normally operated.
 When starting engine or when starting vehicle just after starting engine, brake pedal may vibrate or motor
operating noise may be heard from engine compartment. This is normal condition.
 Brake stopping distance may become longer than models without ABS function depending on the road con-
ditions, when ABS function is operated on slippery r oad like rough road, gravel road or snowy road.
 When a malfunction is indicated, always collect info rmation from the customer about conditions of occur-
rence, estimate cause and perform operation. Check brake booster operation, brake fluid level and brake
fluid leakage, as well as electrical system.
 The optimum performance is achieved by control for V DC function, TCS function, ABS function, EBD func-
tion, hill start assist function or brake limited slip di fferential (BLSD) function when all of brakes, suspensions
PIIB3706J
JPFIA0001ZZ
Revision: 2010 May2011 QX56

PRECAUTIONSBRC-7
< PRECAUTION > [WITH VDC]
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and tires installed on the vehicle are the specified si ze and parts. Brake performance and controllability may
be negatively affected when other parts than the specified are installed.
 Brake stopping distance may become longer and steering stability may be negatively affected, when tires in
different size and combination or other parts than the specified are used.
 When a radio (including wiring), antenna and antenna lead line are located near ABS actuator and electric
unit (control unit), a malfunction or improper operation ma y occur for the control of VDC function, TCS func-
tion, ABS function, EBD function, hill start assist func tion or brake limited slip differential (BLSD) function.
 When the following items are replaced by other parts than genuine parts or modified, ABS warning lamp, brake warning lamp and VDC warning lamp may turn ON, and the control may not operate normally for VDC
function, TCS function, ABS function, EB D function, hill start assist function or brake limited slip differential
(BLSD) function.
- Suspension component parts (shock absorber, spring, bushing and others)
- Tire and wheel (other than the specified size)
- Brake component parts (brake pad, disc rotor, brake caliper and others)
- Engine component parts (ECM, muffler and others)
- Body reinforcement component parts (rollover bar, tower bar and others)
 When suspension, tire and brake component parts are excessively worn or deteriorated and the vehicle is
driven, ABS warning lamp, brake warning lamp and VDC warning lamp may tu\
rn ON, and the control may
not operate normally for VDC function, TCS function, ABS function, EBD function, hill start assist function or
brake limited slip differential (BLSD) function.
 ABS warning lamp, brake warning lamp and VDC warning lamp may turn ON, when only front wheel or rear wheel is rotated using a free roller. This is not a ma lfunction, because it is caused by wheel speed difference
between wheel that is rotated and wheel that is not rota ted. In this case, perform self-diagnosis, check self-
diagnosis results, and erase memory.
 When power supply voltage is not normal, ABS warning lamp, brake warning lamp and VDC warning lamp
turn ON. ABS actuator and electric unit (control unit) st ops control for VDC function, TCS function, ABS func-
tion, EBD function, hill start assist function or brake limited slip differential (BLSD) function. Ordinary brake
operates. After power supply returns to normal, ABS warning lamp, brake warning lamp and VDC warning
lamp turn OFF. The control becomes operative for VD C function, TCS function, ABS function, EBD function,
hill start assist function or brake li mited slip differential (BLSD) function.
 VDC warning lamp may turn ON and VDC function or TCS function may not normally operate, when driving
on a special road the is extremely slanted (bank in a circ uit course). This is not a malfunction if the status
returns to normal for VDC function or TCS function after the engine is started again. In this case, perform
self-diagnosis, check self-diagnosis results, and erase memory.
 A malfunction in yaw rate/side/decel G sensor syste m may be detected when the vehicle sharply turns dur-
ing a spin turn, acceleration turn or drift driving while VDC function or TCS function are OFF (VDC OFF
switch is pressed and VDC OFF indicator lamp is in ON st atus). This is not a malfunction if the status returns
to normal for VDC function or TCS function after the engine is started again. In this case, perform self-diag-
nosis, check self-diagnosis results, and erase memory
Precaution for Harness RepairINFOID:0000000006222558
 Solder the repair part, and wrap it with tape. [Twisted wire fray must be 110 mm (4.33 in) or less.]
SKIB8766E
Revision: 2010 May2011 QX56

COMPONENT PARTSBRC-11
< SYSTEM DESCRIPTION > [WITH VDC]
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4WD
1. ECM Refer to EC-16, "
Component Parts
Location". 2. Control valve & TCM
Refer to TM-10, "
A/T CONTROL
SYSTEM : Compon ent Parts Loca-
tion". 3. Front wheel sensor
4. ABS actuator and electric unit (con- trol unit) 5. Stop lamp switch 6. Steering angle sensor
7. VDC OFF switch 8. Yaw rate/side/decel G sensor 9. Rear wheel sensor
A. Front wheel hub and bearing assem- bly B. Inside engine room C. Brake pedal
D. ABS warning lamp, brake warning lamp, VDC warning lamp, VDC OFF
indicator lamp E. Back of spiral cable assembly F. Center console assembly
G. Under center console assembly H. Rear wheel hub and bearing assem- bly
Revision: 2010 May2011 QX56

BRC-12
< SYSTEM DESCRIPTION >[WITH VDC]
COMPONENT PARTS
1. Transfer control unit
Refer to DLN-10, "
Component Parts
Location". 2. ECM
Refer to EC-16, "
Component Parts
Location". 3. Control valve & TCM
Refer to TM-10, "
A/T CONTROL
SYSTEM : Component Parts Loca-
tion".
4. Front wheel sensor 5. ABS actuat or and electric unit (con-
trol unit) 6. Stop lamp switch
7. Steering angle sensor 8. VDC OFF switch 9. Yaw rate/side/decel G sensor
10. Rear wheel sensor
A. Front wheel hub and bearing assem- bly B. Inside engine room C. Brake pedal
JPFIC0186ZZ
Revision: 2010 May2011 QX56

COMPONENT PARTSBRC-13
< SYSTEM DESCRIPTION > [WITH VDC]
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Component DescriptionINFOID:0000000006222560
*1: Models with Advanced Driver Assistance System
*2: Models with 4WD system
D. ABS warning lamp, brake warning lamp, VDC warning lamp, VDC OFF
indicator lamp E. Back of spiral cable assembly F. Center console assembly
G. Under center console assembly H. Rear wheel hub and bearing assem- bly
Component Reference/Function
ABS actuator and electric unit
(control unit) Motor/accumulator assembly
BRC-14, "
ABS Actuator and Electric Unit (Control Unit)"
Motor relay
Actuator relay (main relay)
ABS IN valve
ABS OUT valve
Cut valve 1
Cut valve 2
Suction valve 1
Suction valve 2
Control pressure sensor
*1
Accumulator pressure sensor
Master cylinder pressure sensor
Wheel sensor BRC-14, "
Wheel Sensor and Sensor Rotor"
Stop lamp switchBRC-15, "Stop Lamp Switch"
Steering angle sensorBRC-15, "Steering Angle Sensor"
Yaw rate/side/decel G sensorBRC-15, "Yaw Rate/Side/Decel G sensor"
Brake fluid level switch BRC-15, "Brake Fluid Level Switch"
Parking brake switchBRC-15, "Parking Brake Switch"
VDC OFF switchBRC-15, "VDC OFF Switch"
ECMMainly transmits the
following signals to ABS actuator and elec-
tric unit (control unit) via CAN communication.
 Accelerator pedal position signal
 Engine speed signal
Mainly receives the following signals from ABS actuator and
electric unit (control unit) via CAN communication.
 Target throttle position signal
TCM Mainly transmits the
following signals to ABS actuator and elec-
tric unit (control unit) via CAN communication.
 Shift position signal
 Current gear position signal
Transfer control unit
*2Mainly transmits the following signals to ABS actuator and elec-
tric unit (control unit) via CAN communication.
 Current 4WD mode signal
ABS warning lamp
BRC-16, "
System Description"Brake warning lamp
VDC warning lamp
VDC OFF indicator lamp
Revision: 2010 May2011 QX56

BRC-14
< SYSTEM DESCRIPTION >[WITH VDC]
COMPONENT PARTS
ABS Actuator and Electric Unit (Control Unit)
INFOID:0000000006222561
Electric unit (control unit) is in tegrated with actuator and motor/accumulator assembly and comprehensively
controls VDC function, TCS function, AB S function, EBD function, hill start assist function or brake limited slip
differential function.
ELECTRIC UNIT (CONTROL UNIT)
 Brake fluid pressure, engine and transmission are controlled according to signals from each sensor.
 If malfunction is detected, the system enters fail-safe mode.
ACTUATOR
The following components are integrated with ABS actuator.
Motor/accumulator Assembly
Pump Operates the pump drive according to signals from ABS actuator and electric unit (control unit) by the motor.
Motor Operates the motor drive according to signals fr om ABS actuator and electric unit (control unit).
Accumulator
 The accumulator accumulates brake fluid conveyed by the motor and pump.
Motor Relay
Operates the motor ON/OFF according to signals fr om ABS actuator and electric unit (control unit).
Actuator Relay (Main Relay)
Operates each valve ON/OFF according to signals fr om ABS actuator and electric unit (control unit).
ABS IN Valve and ABS OUT Valve
Increases, holds or decreases the fluid pressure of each caliper according to signals from ABS actuator and
electric unit (control unit).
Cut Valve 1, Cut Valve 2
Shuts off the ordinary brake line from master cylinder to signals from ABS actuator and electric unit (control
unit).
Suction Valve 1
Suction Valve 1 switches the brake path to convey accu mulator pressure to the front system, according to a
signal transmitted from the ABS actuat or and electric unit (control unit).
Suction Valve 2
Suction valve 2 releases accumulator pressure, accord ing to a signal transmitted from the ABS actuator and
electric unit (control unit).
Control Pressure Sensor (models with Advanced Driver Assistance System)
Detects the brake fluid pressure of brake caliper side and transmits a signal to ABS actuator and electric unit
(control unit).
Accumulator Pressure Sensor
The accumulator pressure sensor detects brake fluid pressure accumulated in the accumulator and conveys
the detected result to the ABS act uator and electric unit (control unit).
Master cylinder Pressure Sensor
Detects the brake fluid pressure of master cylinder part and transmits a signal to ABS actuator and electric unit
(control unit).
Wheel Sensor and Sensor RotorINFOID:0000000006222562
NOTE:
 Wheel sensor and sensor rotor is integrated in wheel hub assembly.
 Never measure resistance and voltage value using a tester because sensor is active sensor.
Revision: 2010 May2011 QX56