2011 INFINITI QX56 parking brake

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

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

BRC-1
BRAKES
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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

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

COMPONENT PARTSBRC-15
< SYSTEM DESCRIPTION > [WITH VDC]
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 Downsize and weight reduction is aimed. IC for detection portion and magnet for sensor rotor are adopted.
 Power supply is supplied to detection portion so that magnetic field
line is read. Magnetic field that is detected is converted to current
signal.
 When sensor rotor rotates, magnetic field changes. Magnetic field
change is converted to current signals (rectangular wave) and is
transmitted to ABS actuator and electric unit (control unit). Change
of magnetic field is pr oportional to wheel speed.
Stop Lamp SwitchINFOID:0000000006222563
Detects the operation status of brake pedal and transmits converted electric signal to ABS actuator and elec-
tric unit (control unit).
Steering Angle SensorINFOID:0000000006222564
Detects the following information and transmits steering angle signal to ABS actuator and electric unit (control
unit) via CAN communication.
 Steering wheel rotation amount
 Steering wheel rotation angular velocity
 Steering wheel rotation direction
Yaw Rate/Side/Decel G sensorINFOID:0000000006222565
Calculates the following information that affects the v ehicle and transmits a signal to ABS actuator and electric
unit (control unit) via communication lines.
 Vehicle rotation angular velocity (yaw rate signal)
 Vehicle lateral acceleration (side G signal) / longitudinal acceleration (decel G signal)
Brake Fluid Level SwitchINFOID:0000000006222566
Detects the brake fluid level in reservoir tank and trans mits converted electric signal from ABS actuator and
electric unit (control unit), when brake fluid level is the specified level or less.
Parking Brake SwitchINFOID:0000000006222567
Detects the operation status of parking brake switch and transmits converted electric signal from combination
meter to ABS actuator and electric unit (control unit).
VDC OFF SwitchINFOID:0000000006222568
 VDC OFF switch is integrated in SNOW MODE / TOW MODE / VDC OFF switch assembly (2WD models) or
4WD switch assembly (4WD models).
 The operation of the VDC OFF switch enables the arbi trary switching of the VDC function between stop sta-
tus and standby status. The status of the function is indicated by the VDC OFF indicator lamp. (ON: Non-
operational status, OFF: Standby status)
- VDC function NOTE:
Brake limited slip differentia l (BLSD) control operates.
- TCS function
 VDC OFF indicator lamp turns OFF (standby status) when the engine is started again after it is stopped once while VDC OFF indicator lamp is ON (non-operational status).
JPFIC0131GB
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

BRC-42
< SYSTEM DESCRIPTION >[WITH VDC]
DIAGNOSIS SYSTEM [
ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)]
Note 1: Refer to BRC-16, "System Description" for ON/OFF conditions of each warning lamp and indicator
lamp.
Note 2: Models with 4WD System
Note 3: Models with Advanced Driver Assistance System
Note 4: USS means “hill start assist”
ACTIVE TEST
The active test is used to determine and identify details of a malfunction, based on self-diagnosis test result
sand data obtained in the DATA MONITOR. In response to instructions from CONSULT-III, instead of those
SV2
(On/Off) Suction valve 2 operation status is displayed.
STOP LAMP SW2
(On/Off) Stop lamp switch signal input status is displayed.
ACCEL POS SIG
(%) ×
Displays the Accelerator pedal position
SIDE G-SENSOR
(m/s
2) ×
Side G detected by side G sensor is displayed.
STR ANGLE SIG
( ° ) ×
Steering angle detected by steering angle sensor is dis-
played.
PRESS SENSOR
(bar) ×Detects the brake fluid pressure of master cylinder part is
displayed.
ACCUM PRESS SEN
(bar) Detects the brake fluid pressure of accumulator is dis-
played.
CONT PRESS SEN
(Note 3)
(bar) Detects the brake fluid pressure of control pressure sensor
is displayed
EBD SIGNAL
(On/Off) EBD operation status is displayed.
ABS SIGNAL
(On/Off) ABS operation status is displayed.
TCS SIGNAL
(On/Off) TCS operation status is displayed.
VDC SIGNAL
(On/Off) VDC operation status is displayed.
EBD FAIL SIG
(On/Off) EBD fail-safe signal status is displayed.
ABS FAIL SIG
(On/Off) ABS fail-safe signal st
atus is displayed.
TCS FAIL SIG
(On/Off) TCS fail-safe signal status is displayed.
VDC FAIL SIG
(On/Off) VDC fail-safe signal status is displayed.
CRANKING SIG
(On/Off) Cranking status is displayed.
FLUID LEV SW
(On/Off) ×Brake fluid level signal input status via CAN communication
is displayed.
PARK BRAKE SW
(On/Off) ×Parking brake switch signal input status via CAN communi-
cation is displayed.
STP ON RLY
(On/Off) Stop lamp switch relay status is displayed.
USS SIG
(Note 4)
(On/Off) hill start assist operation status is displayed.
Item (Unit)
Monitor item selection
Note
INPUT SIGNALS MAIN ITEMS
Revision: 2010 May2011 QX56