2011 INFINITI QX56 steering

BR-6
< SYMPTOM DIAGNOSIS >
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
SYMPTOM DIAGNOSIS
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NVH Troubleshooting ChartINFOID:0000000006222461
Use the chart below to find the cause of the symp tom. If necessary, repair or replace these parts.
×: ApplicableReference page
BR-16
,
BR-18
BR-16
, BR-18
BR-36
, BR-42
BR-16
, BR-18
BR-16
, BR-18
BR-16
, BR-18
BR-16
, BR-18
BR-16
, BR-18
BR-16
, BR-18
BR-16
, BR-18
NVH in PB section
NVH in DLN section
NHV in DLN section
NVH in FAX, RAX and FSU, RSU section
NVH in WT section
NVH in WT section
NVH in FAX, RAX section
NVH in ST section
Possible cause and
SUSPECTED PARTS
Pads damaged
Pads uneven wear
Shims damaged
Rotor imbalance
Rotor damage
Rotor runout
Rotor deformation
Rotor deflection
Rotor rust
Rotor thickness variation
Drum out of round
PROPELLER SHAFT
DIFFERENTIAL
AXLE AND SUSPENSION
TIRE
ROAD WHEEL
DRIVE SHAFT
STEERING
Symptom BRAKE Noise
××× ×× ×××
××
Shake ×××××
××
Shimmy, Judder ××××××× ××× ×
Revision: 2010 May2011 QX56

BR-24
< REMOVAL AND INSTALLATION >
BRAKE PIPING
Never reuse the copper washer.
3. Install the brake hose L-pin by aligning it with the brake caliper assembly positioning hole, and tighten the union bolt (1) to the
specified torque.
4. Install the brake tube to the brake hose, temporarily tighten the flare nut by hand until it does not rotate further, and fix the brake
hose to the bracket with the lock plate.
CAUTION:
Check that all brake hose or brake tube are not twisted and
bent.
5. Tighten the flare nut to the specified torque with a crowfoot and torque wrench.
CAUTION:
Never scratch the flare nut and the brake tube.
6. Tighten the brake hose mounting nuts to the specified torque. CAUTION:
Never reuse the brake hose mounting nuts.
7. Perform the air bleeding. Refer to BR-11, "
Bleeding Brake System".
8. Install tires with power tool. Refer to WT-64, "
Exploded View".
9. Perform inspection after installation. Refer to BR-24, "
FRONT : Inspection".
FRONT : InspectionINFOID:0000000006222478
INSPECTION AFTER INSTALLATION
1. Check the brake hoses and tubes for the following: no scratches; no twist and deformation; no interfer-
ence with other components when steering the steering wheel; no looseness at connections.
2. Depress the brake pedal with a force of 785 N (80 kg, 176 lb) and hold down the pedal for approx. 5 sec- onds with the engine running. Check for any fluid leakage.
CAUTION:
Retighten the applicable connection to the specified torque and repair any abnormal (damaged,
worn or deformed) part if any brake fluid leakage is present.
REAR
JPFIA0012ZZ
Revision: 2010 May2011 QX56

BR-26
< REMOVAL AND INSTALLATION >
BRAKE PIPING
REAR : Removal and Installation
INFOID:0000000006222481
REMOVAL
CAUTION:
 If the brake fluid adheres to the brake caliper assembly and disc rotor, quickly wipe it off.
 Never spill or splash brake fluid on painted surfaces. Brake fluid may seriously damage paint. Wipe it
off immediately and wash with wate r if it gets on a painted surface.
 Never depress the brake pedal. Brake fluid may spl ash while removing the brake hose or brake tube.
1. Remove tires with power tool.
2. Drain brake fluid. Refer to BR-10, "
Draining".
3. Loosen the flare nut with a flare nut wrench and separate the brake tube and the brake hose. CAUTION:
 Never scratch the flare nut and the brake tube.
 Never bend sharply, twist or strongly pull out the brake hose or brake tube.
 Cover open end of brake hose or brake tube wh en disconnecting to prevent entrance of dirt.
4. Remove the union bolt and copper washers, and remove the brake hose from the brake caliper assembly.
5. Remove the lock plate and remove the brake hose.
INSTALLATION
CAUTION:
 If the brake fluid adheres to the brake caliper assembly and disc rotor, quickly wipe it off.
 Never spill or splash brake fluid on painted surfaces. Brake fluid may seriously damage paint. Wipe it
off immediately and wash with wate r if it gets on a painted surface.
 Never depress the brake pedal. Brake fluid may spl ash while removing the brake hose or brake tube.
1. Assemble the union bolt and the copper washers to the brake hose. CAUTION:
Never reuse the copper washer.
2. Align the brake hose pin to the projection (A) of the brake caliper
assembly and tighten the union bolt (1) to the specified torque.
3. Install the brake tube to the brake hose, temporarily tighten the flare nut by hand until it does not rotate further, and fix the brake
hose to the bracket with the lock plate.
CAUTION:
Check that all brake hose or brake tube are not twisted and
bent.
4. Tighten the flare nut to the specified torque with a crowfoot and torque wrench.
CAUTION:
Never scratch the flare nut and the brake tube.
5. Perform the air bleeding. Refer to BR-11, "
Bleeding Brake System".
6. Install tires with power tool. Refer to WT-64, "
Exploded View".
7. Perform inspection after installation. Refer to BR-26, "
REAR : Inspection".
REAR : InspectionINFOID:0000000006222482
INSPECTION AFTER INSTALLATION
1. Check the brake hoses and tubes for the following: no scratches; no twist and deformation; no interfer-
ence with other components when steering the steering wheel; no looseness at connections.
1. Front disc brake 2. Connector 3. Hydraulic booster assembly
4. Rear disc brake
A. Brake hose B. Brake tube
: Flare nut
: Union bolt
JPFIA0099ZZ
Revision: 2010 May2011 QX56

BRC-1
BRAKES
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SECTION BRC
A
B
BRC
N
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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-3
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BRC
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VDC OFF SWITCH ......................................... ..119
Component Function Check ................................ ..119
Diagnosis Procedure .............................................119
Component Inspection ..........................................120
ABS WARNING LAMP ................................... ..122
Component Function Check ................................ ..122
Diagnosis Procedure .............................................122
BRAKE WARNING LAMP ...............................123
Component Function Check ................................ ..123
Diagnosis Procedure .............................................123
VDC WARNING LAMP .....................................125
Component Function Check ................................ ..125
Diagnosis Procedure .............................................125
VDC OFF INDICATOR LAMP ..........................126
Component Function Check ................................ ..126
Diagnosis Procedure .............................................126
SYMPTOM DIAGNOSIS ............................127
EXCESSIVE OPERATION FREQUENCY ...... ..127
Description .......................................................... ..127
Diagnosis Procedure .............................................127
UNEXPECTED BRAKE PEDAL REACTION ...128
Description .......................................................... ..128
Diagnosis Procedure .............................................128
THE BRAKING DISTANCE IS LONG ..............129
Description .......................................................... ..129
Diagnosis Procedure .............................................129
DOES NOT OPERATE .....................................130
Description .......................................................... ..130
Diagnosis Procedure .............................................130
BRAKE PEDAL VIBRATION OR OPERA-
TION SOUND OCCURS ...................................
131
Description .......................................................... ..131
Diagnosis Procedure .............................................131
VEHICLE JERKS DURING ..............................132
Description .......................................................... ..132
Diagnosis Procedure .............................................132
NORMAL OPERATING CONDITION ...............133
Description .......................................................... ..133
REMOVAL AND INSTALLATION .............134
WHEEL SENSOR ........................................... ..134
FRONT WHEEL SENSOR ..................................... ..134
FRONT WHEEL SENSOR : Exploded View .........134
FRONT WHEEL SENSOR : Removal and Instal-
lation ......................................................................
134
REAR WHEEL SENSOR ....................................... ..135
REAR WHEEL SENSOR : Exploded View ...........135
REAR WHEEL SENSOR : Removal and Installa-
tion ....................................................................... ..
135
SENSOR ROTOR ............................................136
FRONT SENSOR ROTOR ..................................... ..136
FRONT SENSOR ROTOR : Removal and Instal-
lation ......................................................................
136
REAR SENSOR ROTOR ....................................... ..136
REAR SENSOR ROTOR : Removal and Installa-
tion .........................................................................
136
ABS ACTUATOR AND ELECTRIC UNIT
(CONTROL UNIT) ...........................................
137
Removal and Installation .......................................137
YAW RATE/SIDE/DECEL G SENSOR ...........138
Exploded View .......................................................138
Removal and Installation .......................................138
STEERING ANGLE SENSOR .........................139
Removal and Installation .......................................139
VDC OFF SWITCH ..........................................140
Removal and Installation .......................................140
BRAKE ASSIST (WITH PREVIEW FUNC-
TION)
PRECAUTION ............... .............................
141
PRECAUTIONS ...............................................141
Precautions for Preview Function Service ........... ..141
SYSTEM DESCRIPTION ...........................142
COMPONENT PARTS ....................................142
Component Parts Location .................................. ..142
Component Description .........................................143
SYSTEM ..........................................................145
BRAKE ASSIST (WITH PREVIEW FUNCTION) ... ..145
BRAKE ASSIST (WITH PREVIEW FUNCTION) :
System Description ................................................
145
DTC/CIRCUIT DIAGNOSIS .......................146
BRAKE ASSIST (WITH PREVIEW FUNC-
TION) ...............................................................
146
Diagnosis Procedure ........................................... ..146
SYMPTOM DIAGNOSIS ............................147
NORMAL OPERATING CONDITION .............147
Description ........................................................... ..147
INTELLIGENT BRAKE ASSIST
PRECAUTION ............... .............................
148
PRECAUTIONS ...............................................148
Precautions for IBA System Service .................... ..148
Revision: 2010 May2011 QX56

PRECAUTIONSBRC-5
< PRECAUTION > [WITH VDC]
C
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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