2011 INFINITI QX56 brake fluid

REAR DISC BRAKEBR-45
< REMOVAL AND INSTALLATION >
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5. Remove piston seal from cylinder body using suitable tool. CAUTION:
Be careful not to damage a cylinder inner wall.
6. Remove bleeder valve and cap.
7. Perform inspection after disassembly. Refer to BR-45, "
BRAKE
CALIPER ASSEMBLY : Inspection".
ASSEMBLY
1. Install bleeder valve and cap.
2. Apply rubber grease to piston seal (1), and install them to cylin-
der body.
CAUTION:
Never reuse piston seal.
3. Apply rubber grease to piston boot (1). Cover the piston (2) end with piston boot, and then install cylinder side lip on piston boot
securely into a groove on cylinder body.
CAUTION:
Never reuse piston boot.
4. Apply new brake fluid to piston (1). Push piston into cylinder body by hand and push piston boot (2) piston-side lip into the
piston groove.
CAUTION:
Press the piston evenly and var y the pressing point to pre-
vent cylinder inner wall from being rubbed.
5. Apply rubber grease to bushing, and install bushing to sliding pin bolt.
6. Apply rubber grease to sliding pin boots, and install sliding pin boots to torque member.
7. Apply rubber grease to sliding pin, and install the cylinder body.
8. Install sliding pin bolts and tighten it to the specified torque.Refer to BR-42, "
BRAKE CALIPER ASSEM-
BLY : Exploded View".
BRAKE CALIPER ASSEMBLY : InspectionINFOID:0000000006222501
INSPECTION AFTER DISASSEMBLY
Check the following items and replace if necessary.
Cylinder Body
Check the cylinder inner wall for rust, wear, cracks or damage.
JPFIA0738ZZ
JPFIA0039ZZ
JPFIA0739ZZ
JPFIA0034ZZ
Revision: 2010 May2011 QX56

BR-46
< REMOVAL AND INSTALLATION >
REAR DISC BRAKE
CAUTION:
Always clean with new brake fluid. Never clean with mineral oil such as gasoline and light oil.
Torque Member
Check the torque member for rust, wear, cracks or damage.
Piston
Check the surface of the piston for rust, wear, cracks or damage.
CAUTION:
A piston sliding surface is plat ed. Never polish with sandpaper.
Sliding Pin, Sliding Pin Boot and Bushing
Check the sliding pins, sliding pin boots and bushing for rust, wear, cracks or damage.
INSPECTION AFTER INSTALLATION
1. Check a drag of rear disc brake. If any dr ag is found, follow the procedure described below.
2. Remove brake pads. Refer to BR-41, "
BRAKE PAD : Removal and Installation".
3. Press the piston. Refer to BR-41, "
BRAKE PAD : Removal and Installation".
4. Install brake pads. Refer to BR-41, "
BRAKE PAD : Removal and Installation".
5. Depress the brake pedal several times.
6. Check a drag of rear disc brake again. If any drag is found, disassemble the caliper. Refer to BR-44,
"BRAKE CALIPER ASSEMBLY : Disassembly and Assembly".
7. Burnish contact surfaces brake pads and disc rotor after refinishing or replacing disc rotor, or if a soft pedal occurs at very low mileage. Refer to BR-18, "
DISC ROTOR : Inspection and Adjustment".
Revision: 2010 May2011 QX56

SERVICE DATA AND SPECIFICATIONS (SDS)
BR-47
< SERVICE DATA AND SPECIFICATIONS (SDS)
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SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
General SpecificationINFOID:0000000006222502
Unit: mm (in)
Brake PedalINFOID:0000000006222503
Unit: mm (in)
Brake BoosterINFOID:0000000006222504
Unit: mm (in)
Front Disc BrakeINFOID:0000000006222505
Unit: mm (in)
Rear Disc BrakeINFOID:0000000006222506
Unit: mm (in)
Front brake Cylinder bore diameter 50.8 (2.000)
× 2
Pad length × width × thickness 151.6 (5.97) × 56.5 (2.224) × 12.0 (0.472)
Rotor outer diameter × thickness 350 (13.78) × 30.0 (1.181)
Rear brake Cylinder bore diameter 48.1 (10894)
Pad length
× width × thickness 110.0 (4.43) × 41.0 (1.614) × 9.0 (0.354)
Rotor outer diameter × thickness 350 (13.78) × 20.0 (0.787)
Control valve Valve type Electric brake force distribution
Recommended brake fluid Refer to MA-10, "
Fluids and Lubricants".
Item Standard
Brake pedal height 168.5 (6.63) – 178.5 (7.03)
Depressed brake pedal height
[Depressing 490 N (50 kg, 110 lb) while turning the engine ON] 100 (3.94) or more
Clearance between stop lamp switch and brake switch threaded end and the
brake pedal bracket 0.2 (0.008) – 1.96 (0.0772)
Brake pedal play 3 (0.12) – 11 (0.43)
Item Standard
Input rod length 202.2 (7.96)
Item Limit
Brake pad Wear thickness 1.5 (0.059)
Disc rotor Wear thickness 28.5 (1.122)
Thickness variation (measured at 8 positions) 0.015 (0.0006)
Runout (with it attached to the vehicle) 0.053 (0.0021)
Item Limit
Brake pad Wear thickness 2.0 (0.079)
Disc rotor Wear thickness 18.0 (0.709)
Thickness variation (measured at 8 positions) 0.015 (0.0006)
Runout (with it attached to the vehicle) 0.05 (0.0020)
Revision: 2010 May2011 QX56

BRC-1
BRAKES
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SECTION BRC
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CONTENTS
BRAKE CONTROL SYSTEM
WITH VDC
PRECAUTION ................ ...............................
5
PRECAUTIONS .............................................. .....5
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
5
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
5
Precaution for Procedure without Cowl Top Cover ......6
Precaution for Brake System ....................................6
Precaution for Brake Control System ........................6
Precaution for Harness Repair ..................................7
PREPARATION ............................................9
PREPARATION .............................................. .....9
Commercial Service Tools .................................. ......9
SYSTEM DESCRIPTION .............................10
COMPONENT PARTS ................................... ....10
Component Parts Location .................................. ....10
Component Description ...........................................13
ABS Actuator and Electric Unit (Control Unit) .........14
Wheel Sensor and Sensor Rotor ............................14
Stop Lamp Switch ...................................................15
Steering Angle Sensor ............................................15
Yaw Rate/Side/Decel G sensor ...............................15
Brake Fluid Level Switch .........................................15
Parking Brake Switch ..............................................15
VDC OFF Switch .....................................................15
SYSTEM .............................................................16
System Description ............................................. ....16
Fail-safe ..................................................................25
Protection Function .................................................28
VDC FUNCTION .................................................... ....28
VDC FUNCTION : System Description ...................28
TCS FUNCTION ..................................................... ....31
TCS FUNCTION : System Description ....................31
ABS FUNCTION .................................................... ....32
ABS FUNCTION : System Description ....................33
EBD FUNCTION .................................................... ....34
EBD FUNCTION : System Description ....................34
HILL START ASSIST FUNCTION ......................... ....36
hill start assist FUNCTION : System Description ....36
BRAKE LIMITED SLIP DIFFERENTIAL (BLSD)
FUNCTION ............................................................. ....
37
BRAKE LIMITED SLIP DIFFERENTIAL (BLSD)
FUNCTION : System Description ............................
37
DIAGNOSIS SYSTEM [ABS ACTUATOR
AND ELECTRIC UNIT (CONTROL UNIT)] .......
40
CONSULT-III Function ............................................40
ECU DIAGNOSIS INFORMATION ..............45
ABS ACTUATOR AND ELECTRIC UNIT
(CONTROL UNIT) .............................................
45
Reference Value .................................................. ....45
Fail-safe ...................................................................47
Protection Function ..................................................50
DTC Inspection Priority Chart ..................................50
DTC Index ...............................................................51
WIRING DIAGRAM ......................................53
BRAKE CONTROL SYSTEM ...........................53
Wiring Diagram .................................................... ....53
BASIC INSPECTION ...................................60
DIAGNOSIS AND REPAIR WORK FLOW .......60
Work Flow ............................................................ ....60
Diagnostic Work Sheet ............................................61
Revision: 2010 May2011 QX56

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

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

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