2011 INFINITI QX56 wheel

STEERING GEAR AND LINKAGEST-43
< REMOVAL AND INSTALLATION >
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4. Remove cotter pin (1), and then loosen the nut.
5. Remove steering outer socket (2) from steering knuckle (3) so as not to damage ball joint boot (4) using suitable ball joint
remover (commercial service tool).
CAUTION:
Temporarily tighten the nut to prevent damage to threads
and to prevent the ball joint remover from suddenly coming
off.
6. Remove high pressure piping and low pressure piping of hydraulic piping, and then drain power steering fluid.
7. Remove power steering solenoid valve harness connector.
8. Remove lower joint fixing bolt (steering gear side).
9. Separate the lower joint from the steering gear assembly. Refer to ST-37, "
Exploded View".
CAUTION:
 When removing lower joint, n ever insert a tool, such as a screw driver, into the yoke groove to
pull out the lower joint. In case of the violation of the above, replace lower joint with a new one.
 Spiral cable may be cut if steering wheel tu rns while separating steering column assembly and
steering gear assembly. Be sure to secure st eering wheel using string to avoid turning.
10. Remove steering gear assembly.
INSTALLATION
Note the following, and install in the reverse order of removal.
CAUTION:
Spiral cable may be cut if steering wheel turns while separating steering column assembly and steer-
ing gear assembly. Be sure to secure steer ing wheel using string to avoid turning.
 When installing lower joint to steering gear assembly, follow the procedure listed below.
- Set rack of steering gear in the neutral position.
NOTE:
To get the neutral position of rack, turn gear-sub a ssembly and measure the distance of inner socket, and
then measure the intermediat e position of the distance.
- Align rear cover cap projection (A) with the marking position of gear housing assembly (B).
- Install slit part of lower joint (C) aligning with the rear cover cap projection (A). Make sure that the slit part of lower joint (C) is
aligned with rear cover cap projection (A) and the marking position
of gear housing assembly (B).
 Never reuse cotter pin and steering gear mounting nut.
 Perform inspection after installation. Refer to ST-46, "
Inspection".
Disassembly and AssemblyINFOID:0000000006225609
DISASSEMBLY
CAUTION:
 Disassemble and assemble steering gear assembly by fixing the mounting area with a vise using
copper plates.
 Clean steering gear assembly with kerosene before disassembling. Be careful to avoid splashing or
applying any kerosene over connector of discharge port or return port.
1. Remove cylinder tubes from gear housing assembly.
2. Remove rear cover cap from gear-sub assembly.
PGIA0063E
: Bolt
JPGIA0038ZZ
Revision: 2010 May2011 QX56

STEERING GEAR AND LINKAGEST-47
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 Hook a spring balance at the point shown in the figure and pull the spring balance. Make sure that the spring balance reads the spec-
ified value when ball stud and inner socket start to move. Replace
outer socket and inner socket if they are outside the standard.
BALL JOINT ROTATING TORQUE
 Make sure that the reading is within the following specified rangeusing preload gauge (A) [SST: ST3127S000 (J-25765-A)]. Replace
outer socket if the reading is outside the specified value.
BALL JOINT AXIAL END PLAY
 Apply an axial load of 490 N (50 kg, 110 lb) to ball stud. Using adial gauge, measure amount of stud movement, and then make
sure that the value is within the following specified range. Replace
outer socket (1) and inner socket (2) if the measured value is out-
side the standard.
INSPECTION AFTER INSTALLATION
 After installation, bleed air from the steering hydraulic system. Refer to ST-30, "Inspection".
 Check if steering wheel turns smoothly when it is turned several times fully to the end of the left and right.
 Check the steering wheel play, neutral position steeri ng wheel, steering wheel turning force, and front wheel
turning angle. Refer to ST-32, "
Inspection".
 Check the fluid level, fluid leakage, and air bleeding hydraulic system. Refer to ST-30, "
Inspection".
 Perform final tightening of nuts and bolts on each part under unladen conditions with tires on level ground when removing steering gear assembly. Check wheel alignment. Refer to FSU-7, "
Inspection".
 Adjust neutral position of steering angle sensor after checking wheel alignment. Refer to BRC-64, "
Work
Procedure".
Outer socket
(Measuring point: Stud cotter pin mounting hole)
Spring balance measure-
ment : Refer to
ST-58, "
Socket
Swing Force and Rotating
To r q u e".
Inner socket (Measuring point: “*” mark shown in the figure)
Spring balance measure-
ment : Refer to
ST-58, "
Socket
Swing Force and Rotating
To r q u e".
Outer socket rotat-
ing torque : Refer to
ST-58, "
Socket Swing
Force and Rotating Torque".
SGIA0896E
SGIA1382E
Outer socket : Refer to ST-58, "Socket Axial End Play".
Inner socket : Refer to ST-58, "
Socket Axial End Play".
JSGIA0109ZZ
Revision: 2010 May2011 QX56

ST-56
< REMOVAL AND INSTALLATION >
HEATED STEERING WHEEL SWITCH
HEATED STEERING WHEEL SWITCH
Exploded ViewINFOID:0000000006225616
Removal and InstallationINFOID:0000000006225617
REMOVAL
1. Remove Instrument center finisher LH and Instrument center finisher RH. Refer to IP-14, "Removal and
Installation".
2. Remove cluster lid C. Refer to IP-14, "
Removal and Installation".
3. Remove cluster lid C lower. Refer to IP-14, "
Removal and Installation".
4. Remove cluster lid C lower (inside) form cluster lid C lower (outside).
5. Remove heated steering wheel switch from cluster lid C lower (inside).
INSTALLATION
Install in the reverse order of removal.
1. Heated steering wheel switch 2. Cluster lid C lower (inside) 3. Cluster lid C lower (outside)
Refer to GI-4, "
Components" for symbols in the figure.
JSGIA0825ZZ
Revision: 2010 May2011 QX56

SERVICE DATA AND SPECIFICATIONS (SDS)
ST-57
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SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
General SpecificationsINFOID:0000000006225618
Steering Wheel Axial End Play and PlayINFOID:0000000006225619
Unit: mm (in)
Steering Wheel Turning ForceINFOID:0000000006225620
Unit: N·m (kg-m, in-lb)
Steering AngleINFOID:0000000006225621
Unit: Degree minute (Decimal degree)
Steering Column LengthINFOID:0000000006225622
Unit: mm (in)
Steering Column Mounting DimensionsINFOID:0000000006225623
Unit: mm (in)
Steering Column Operating RangeINFOID:0000000006225624
Steering gear model Engine speed sensitive type PR32AD
Vehicle speed sensitive type PR32AF
Fluid capacity (Approx.) (lmp qt)1.0 (7/8)
Item Standard
Steering wheel axial end play 0 (0)
Steering wheel play on the outer circumference 0 – 35 (0 – 1.38)
Item Standard
Steering wheel turning force 7.45 (0.76, 66)
Item Standard
Measurement wheel Left side Right side
Inner wheel Minimum 33
°45 ′ (33.75 °)33 °30 ′ (33.50 °)
Nominal 36 °45 ′ (36.75 °)36 °30 ′ (37.50 °)
Maximum 37 °45 ′ (37.75 °)37 °30 ′ (37.50 °)
Outer wheel Nominal 32 °20 ′ (32.33 °)32 °40 ′ (32.67 °)
Item Standard
Column length 529.8 – 533.8 (20.86 – 21.02)
Item Standard
Mounting dimension 34.1 – 36.1 (1.343 – 1.421)
Item Standard
Tilt operating range 74 mm (2.91 in)
Telescopic operating range 40 mm (1.57 in)
Rotating torque 0.49 N· m (0.05 kg-m, 4 in-lb)
Revision: 2010 May2011 QX56

STC-1
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SECTION STC
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CONTENTS
STEERING CONTROL SYSTEM
PRECAUTION ................ ...............................2
PRECAUTIONS .............................................. .....2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
2
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
2
SYSTEM DESCRIPTION ..............................4
COMPONENT PARTS ................................... .....4
Component Parts Location .................................. ......4
Component Description .............................................4
Power Steering Control Unit ......................................4
Power Steering Solenoid Valve .................................4
SYSTEM ..............................................................5
EPS SYSTEM ........................................ ......................5
EPS SYSTEM : System De scription .........................5
EPS SYSTEM : Fail-Safe ..........................................6
ECU DIAGNOSIS INFO RMATION ...............8
POWER STEERING CONTROL UNIT ........... .....8
Reference Value ................................................. ......8
Fail-Safe ....................................................................9
WIRING DIAGRAM ......................................10
ELECTRONICALLY CONTROLLED POWER
STEERING SYSTEM ...................................... ....
10
Wiring Diagram ................................................... ....10
BASIC INSPECTION ...................................13
DIAGNOSIS AND REPAIR WORK FLOW .......13
Work Flow ............................................................ ....13
DTC/CIRCUIT DIAGNOSIS .........................14
POWER SUPPLY AND GROUND CIRCUIT ....14
Diagnosis Procedure ........................................... ....14
POWER STEERING SOLENOID VALVE .........16
Component Function Check ....................................16
Diagnosis Procedure ...............................................16
Component Inspection .............................................17
ENGINE SPEED SIGNAL CIRCUIT ..................18
Diagnosis Procedure ........................................... ....18
VEHICLE SPEED SIGNAL CIRCUIT ................20
Diagnosis Procedure ...............................................20
SYMPTOM DIAGNOSIS ..............................22
UNBALANCE STEERING WHEEL TURNING
FORCE (TORQUE VARIATION) .......................
22
Description ........................................................... ....22
Diagnosis Procedure ...............................................22
REMOVAL AND INSTALLATION ...............23
POWER STEERING CONTROL UNIT ..............23
Removal and Installation ..................................... ....23
Revision: 2010 May2011 QX56

STC-2
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006303358
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 w hether 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 inopera tive, which could increase the risk of personal injury or death in
the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipmen t 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 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation after Battery Disconnect
INFOID:0000000006303360
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect bot h 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 bat tery 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 wi ll remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
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PRECAUTIONSSTC-3
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5. When the repair work is completed, re-connect both 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 ignition switch is turned to LOCK position.)
6. Perform self-diagnosis check of a ll control units using CONSULT-III.
Revision: 2010 May2011 QX56

STC-6
< SYSTEM DESCRIPTION >
SYSTEM
OPERATION PRINCIPLE
During Parking (When Turning The Steering Wheel To The Right.)
1. Power steering solenoid valve is closed while a vehicle is stopped.
2. Pinion “1R”, “2R” and “3R” are closed depending on steering torque of steering wheel.
3. Oil pressure “P” in the gear housing assembly is the sum of oil pressures occurred in “2R” and “3R”. Thisresults in a light steering force because of high pressure.
During High-speed Operation
1. Power steering solenoid valve is opened during high-speed operation.
2. Pinion “1R”, “2R” and “3R” are closed depending on steering torque of steering wheel.
3. Oil pressure “2R” does not occur because the pow er steering solenoid valve is on full throttle.
4. Oil pressure “P” in the gear housing assembly includes only oil pressure occurred in “3R” and results in a heavy steering force.
EPS SYSTEM : Fail-Safe INFOID:0000000006256120
EPS system
 EPS system enters the fail-safe mode (that allows the steering
force to be controlled without impairi ng the drivability) if any of the
input/output values to/from EPS system (power steering control
unit) deviate from the standard range.
 The power steering control unit controls the driving voltage to the
power steering solenoid valve for maintaining the power steering
assist force when the fail-safe function is activated. (The engine
speed signals control EPS system if any vehicle speed signal error
is detected.)
1. Combination meter 2. Power steering control unit 3. Power steering solenoid valve
4. Steering gear assembly 5. Gear housing assembly 6. Gear sub-assembly
7. Pinion 8. Power steering oil pump 9. Reservoir tank
JSGIA0020GB
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Revision: 2010 May2011 QX56