2011 INFINITI QX56 ignition

BR-14
< PERIODIC MAINTENANCE >
BRAKE FLUID
3. Adjust brake fluid level to the reservoir tank MAX line.CAUTION:
Never adjust with the ignition switch ON.
4. Turn the ignition switch ON.
5. Check that the reservoir tank brake fluid level is 4 − 12 mm (0.16
− 0.47 in) lower than the MAX line.
NOTE:
Since brake fluid is in the accumulator in pressurized condition,
the reservoir tank brake fluid level should be lower than the MAX
line.
JPFIA0769ZZ
Revision: 2010 May2011 QX56

HYDRAULIC BOOSTER ASSEMBLYBR-15
< PERIODIC MAINTENANCE >
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HYDRAULIC BOOSTER ASSEMBLY
InspectionINFOID:0000000006222467
OPERATION CHECK
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more. NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Check that the fluid level in the reservoir tank is MAX line.
4. Position the selector lever in P range to release the parking brake.
5. Turn the ignition switch ON to check the time between motor activation and motor stop.
6. After the motor is stopped, check that the ABS warning lamp and the VDC warning lamp in the combina- tion meter are OFF when the engine is started.
7. Stop the engine (ignition switch OFF).
8. Turn the ignition switch ON and depress the brake pedal 4 to 5 times to check the time between motor activation and motor stop.
9. Turn the ignition switch OFF. Turn the ignition switch ON again. Check that the VDC warning lamp turns ON when the brake pedal is depressed 15 to 20 times.
10. Check that the VDC warning lamp turns ON when the brake pedal is depressed 15 to 20 times after the lapse of 120 seconds or more after the ignition switch is turned ON again.
11. Perform the self-diagnosis for “ABS” with CONSULT-III and erase self-diagnosis results.
FUNCTION CHECK
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more.
NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Turn the ignition switch ON with the brake pedal depr essed to check that the clearance between the brake
pedal and the dash lower panel decreases. Motor operating time : 18 seconds or less
Motor operating time : 2
− 11 seconds
Revision: 2010 May2011 QX56

HYDRAULIC BOOSTER ASSEMBLYBR-29
< REMOVAL AND INSTALLATION >
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Removal and InstallationINFOID:0000000006222484
REMOVAL
1. Turn the ignition switch OFF. CAUTION:
Never turn the ignition switch ON before th e completion of the installation procedure.
2. Drain brake fluid. Refer to BR-10, "
Draining".
3. Depress the brake pedal 20 times or more to release the pressure from the accumulator. CAUTION:
Always perform this step before re moving the hydraulic booster assembly.
4. Disconnect hydraulic booster assembly harness connector.
5. Separate the brake tube from hydraulic booste r assembly with a flare nut wrench. Refer to BR-22,
"FRONT : Exploded View".
6. Remove brake tube from clip.
1. Reservoir cap 2. Lab el 3. Reservoir tank
4. Pin 5. Motor/accumulator assembly 6. Brake tube
7. Brake hose assembly 8. Grommet 9. Harness band
10. Collar 11. Bushing 12. Pin mount
13. Grommet 14. Bracket 15. Cap
16. Bushing 17. Bracket 18. ABS actuator and electric unit (con- trol unit)
19. Gasket 20. Spacer
: Apply brake fluid.
Refer to GI-4, "
Components" for symbols not described on the above.
JPFIA0748GB
Revision: 2010 May2011 QX56

BR-30
< REMOVAL AND INSTALLATION >
HYDRAULIC BOOSTER ASSEMBLY
7. Remove snap pin (1) and clevis pin (2) from clevis.
8. Remove nuts on hydraulic booster assembly and brake pedalassembly.
CAUTION:
Hold the hydraulic booster assembly so as to avoid drop-
ping out.
9. Remove hydraulic booster assembly. CAUTION:
 Always hold (A) when removi ng the hydraulic booster
assembly.
 Never deform or bend the brake tubes when removing the hydraulic booster assembly.
 Always use a cushion or an equivalent to place the hydraulic booster assembly. Failure to do this may cause
uneven loads or impact and result in a malfunction.
10. After replacing hydraulic booster assembly, always follow the accumulator disposal procedure to discard the hydraulic booster
assembly. Refer to BR-33, "
Disposal".
INSTALLATION
Note the following, and install in the reverse order of removal.
 Perform adjustment before installation. Refer to BR-32, "
Inspection and Adjustment".
 Never reuse a hydraulic booster assembly after an e xcessive impact. (Slight impulse caused during installa-
tion work is acceptable.)
 Never turn the ignition switch ON before the completion of the installation procedure.
 Be careful not to damage hydraulic booster assembly stud bolt threads. If hydraulic booster assembly is
tilted during installation, the dash panel may damage the threads.
 Always hold (A) when removing the hydraulic booster assembly.
 Never deform or bend the brake tubes when installing the hydraulic booster assembly.
 Always use a new gasket between the hydraulic booster assembly, spacer and the dash panel.
 Replace the clevis pin if it is damaged. Refer to BR-21, "
Inspection
and Adjustment".
 Perform the air bleeding. Refer to BR-11, "
Bleeding Brake Sys-
tem".
 Perform the brake pedal adjustment after installing the brake pedal assembly and hydraulic booster assembly. Refer to BR-7, "
Inspec-
tion and Adjustment".
 Perform inspection after installation. Refer to BR-32, "
Inspection and Adjustment".
Disassembly and AssemblyINFOID:0000000006222485
DISASSEMBLY
CAUTION:
Disassemble the hydraulic booster assembly when necessary.
1. Remove gaskets and spacer from hydraulic booster assembly.
JPFIA0019ZZ
JPFIA0749ZZ
JPFIA0749ZZ
Revision: 2010 May2011 QX56

BR-32
< REMOVAL AND INSTALLATION >
HYDRAULIC BOOSTER ASSEMBLY
 Apply new brake fluid to grommet of between reservoir tank and grommet and ABS actuator and electric unit
(control unit).
Inspection and AdjustmentINFOID:0000000006222486
ADJUSTMENT BEFORE INSTALLATION
Input Rod Length adjustment
1. Loosen the lock nut (1) and adjust the input rod (2) to the speci-
fied length (A).
2. Tighten the lock nut to the specified torque.
INSPECTION AFTER INSTALLATION
Operation Check
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more. NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Check that the fluid level in the reservoir tank is MAX line.
4. Position the selector lever in P range to release the parking brake.
5. Turn the ignition switch ON to check the time between motor activation and motor stop.
6. After the motor is stopped, check that the ABS warn ing lamp and the VDC warning lamp in the combina-
tion meter are OFF when the engine is started.
7. Stop the engine (ignition switch OFF).
8. Turn the ignition switch ON and depress the brake pedal 4 to 5 times to check the time between motor activation and motor stop.
9. Turn the ignition switch OFF. Turn the ignition swit ch ON again. Check that the VDC warning lamp turns
ON when the brake pedal is depressed 15 to 20 times.
10. Check that the VDC warning lamp turns ON when the brake pedal is depressed 15 to 20 times after the lapse of 120 seconds or more after the ignition switch is turned ON again.
11. Perform the self-diagnosis for “ABS” with CONSULT- III and erase all the stored self-diagnosis results.
Function Check
1. Turn the ignition switch OFF.
2. Depress the brake pedal 20 times or more.
NOTE:
The pressure loss in the accumulator results in a large brake pedal stroke. In addition to this, the brake
pedal depression becomes lighter in initial stage.
3. Turn the ignition switch ON with the brake pedal depr essed to check that the clearance between the brake
pedal and the dash lower panel decreases. A : Refer to
BR-47, "
Brake Booster".
JPFIA0728ZZ
Motor operating time : 18 seconds or less
Motor operating time : 2 − 11 seconds
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

BRC-24
< SYSTEM DESCRIPTION >[WITH VDC]
SYSTEM
Rear LH caliper Being returned to reservoir tank through ABS OUT valve, fluid pressure of rear LH caliper is decreased.
Component Parts and Function
*: Models with Advanced Driver Assistance System
CONDITION FOR TURN ON THE WARNING LAMP
ABS Warning Lamp
 Turns ON at the same time as VDC warning lamp
when either ABS function or EBD function is malfunction-
ing.
 Turns ON when ignition switch turns ON and turns OFF when the system is normal, for bulb check purposes.
Brake Warning Lamp
 Turns ON at the same time as ABS warning lamp and VDC warning lamp when EBD function, motor/accu- mulator assembly or motor system is malfunctioning.
 Turns ON when ignition switch turns ON and turns OFF when the system is normal, for bulb check purposes.
Component Function
Pump Operates the pump drive according
to signals from ABS actuator and electric unit (control unit) by
the motor.
Motor Operates the motor driv e according to signals from ABS actuator and electric unit (control unit).
Accumulator The accumulator accumulates brake fluid conveyed by the motor and pump.
ABS IN valve Increases, holds or decreases the fluid pressure of each caliper according to signals from ABS ac-
tuator and electric unit (control unit).
ABS OUT valve Increases, holds or decreases the fluid pressure of each caliper according to signals from ABS ac-
tuator and electric unit (control unit).
Cut valve 1
Cut valve 2 Shuts off the ordinary brake line fr
om master cylinder to signals from ABS actuator and electric unit
(control unit).
Suction valve 1 Suction Valve 1 switches the brake line to convey accumulator pressure to the front system, accord-
ing to a signal transmitted from the ABS ac
tuator and electric unit (control unit).
Suction valve 2 Suction valve 2 releases
accumulator pressure, acco rding to a signal transmitted from the ABS ac-
tuator and electric unit (control unit).
Control pressure sensor
*Detects the brake fluid pressure of rear brake caliper 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 actuator 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).
Condition (status) ABS warning lamp
Ignition switch OFF OFF
For approx. 1 seconds after the ignition switch is turned ON ON
Approx. 1 seconds after ignition switch is turned ON (when the
system is in normal operation) OFF
ABS function is ma lfunctioning ON
EBD function is malfunctioning ON
Condition (status) Brake warning lamp
Ignition switch OFF OFF
For approx. 1 seconds after the ignition switch is turned ON ON
Approx. 1 seconds after ignition switch is turned ON (when the
system is in normal operation) OFF
After engine starts OFF
When parking brake operates (parking brake switch ON) ON
Revision: 2010 May2011 QX56