2011 INFINITI QX56 power steering

ST-50
< REMOVAL AND INSTALLATION >
POWER STEERING OIL PUMP
Note the following, and install in the reverse order of removal.
 When installing suction hoses (1), refer to the figure.CAUTION:
 Never apply fluid to the hose (1) and tube (2).
 Insert hose securely until it contacts spool (A) of tube.
 Leave clearance (L) when installing clamp (3).
 When installing eye bolt (1) and copper washer (2) to oil pump (3), refer to the figure.
CAUTION:
 Never reuse copper washer.
 Apply power steering fluid to around copper washers, then
install eye bolt.
 Install eye bolt with eye join t (assembled to high pressure
hose) (B) protrusion (A) facing with pump side cutout, and
then tighten it to the specifi ed torque after tightening by
hand. Refer to ST-54, "
Exploded View".
 Securely insert harness connector to pressure sensor.
 About the installation of drive belt. Refer to EM-20,
"TensionAdjustment".
 Check fluid level, fluid leakage and air bleeding hydr aulic system after the installation. Refer to ST-30,
"Inspection".
Disassembly and AssemblyINFOID:0000000006225613
DISASSEMBLY
CAUTION:
 Fix oil pump with a vise if necessary.
 Use copper plates when fixing with a vise.
1. Perform inspection before disassembly. Refer to ST-52, "
Inspection".
2. Remove rear cover mounting bolts, and then remove rear cover from body assembly.
3. Remove gasket from body assembly.
4. Remove dowel pin, cartridge and side plate from body assembly.
5. Remove pulley mounting nut and washer, then remove pulley from drive shaft.
6. Remove snap ring from drive shaft and press out it. CAUTION:
When removing snap ring, be careful not to damage drive
shaft.
7. Remove oil seal from body assembly using a suitable tool.
8. Remove O-ring from body assembly.
9. Remove mounting bolts of suction pipe, and then remove suc- tion pipe and bracket from body assembly.
10. Remove connector bolt, and then remove O-ring, flow control
valve and spring from body assembly
11. Perform inspection after disassembly. Refer to ST-52, "
Inspec-
tion".
ASSEMBLY
CAUTION:
 Fix oil pump with a vise if necessary.
 Use copper plates when fixing with a vise.L : 3 – 8 mm (0.12 – 0.31 in)
JSGIA0118ZZ
JSGIA0452ZZ
SST010B
Revision: 2010 May2011 QX56

POWER STEERING OIL PUMPST-51
< REMOVAL AND INSTALLATION >
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1. Apply recommended grease to oil seal lips (1). Apply recom- mended fluid to around oil seal. Install oil seal to body assembly,
using a drift.
CAUTION:
Never reuse oil seal.
2. Apply recommended fluid to drive shaft, and press drive shaft into body assembly, then install snap ring.
CAUTION:
Never reuse snap ring.
3. Apply recommended fluid to O-ring, and then install O-ring into body assembly.
CAUTION:
Never reuse O-ring.
4. Install side plate to body assembly.
5. Install dowel pin (1) into dowel pin hole (A), and then install cam ring (2) pointing it's D
1 side toward the body assembly (3) side
as shown in the figure.
 When installing cam ring, turn carved face with a letter E (B) of
it to rear cover.
CAUTION:
Do not confuse the assembling direction of cam ring. If
cam ring is installed facing th e incorrect direction, it may
cause oil pump operation malfunction.
SGIA1150E
SGIA0422E
JSGIA0110ZZ
Revision: 2010 May2011 QX56

ST-52
< REMOVAL AND INSTALLATION >
POWER STEERING OIL PUMP
6. Install rotor to body assembly.CAUTION:
When installing rotor, turn mark face on rotor to body
assembly.
7. Install vane to rotor so that arc of vane faces cam ring side.
8. Check if drive shaft assembly turns smoothly.
9. Install gasket to body assembly. CAUTION:
Never reuse gasket.
10. Install rear cover to body assembly, and then tighten mounting bolts to the specified torque.
11. Install pulley and washer to drive shaft, and then tighten lock nut at the specified torque.
12. Apply recommended fluid to O-ring. Install flow control valve spring, flow control valve and O-ring to body assembly, and then
tighten connector bolt to the specified torque.
CAUTION:
Never reuse O-ring.
13. Apply recommended fluid to O-ring, and then install O-ring to body assembly. CAUTION:
Never reuse O-ring.
14. Install suction pipe and bracket to body assembly.
15. Perform inspection after assembly. Refer to ST-52, "
Inspection".
InspectionINFOID:0000000006225614
INSPECTION BEFORE DISASSEMBLY
Disassemble oil pump only when the following malfunctions occur.
 If oil leakage is found on oil pump.
 Oil pump pulley is damaged or deformed.
 Performance of oil pump is low.
INSPECTION AFTER DISASSEMBLY
Body Assembly and Rear Cover Inspection
Check body assembly and rear cover for internal damage. Replace oil pump assembly if necessary.
Cartridge Assembly Inspection
Check cam ring, rotor and vane for damage. Replace oil pump assembly if necessary.
Side Plate Inspection
Check side plate for damage. Replace oil pump assembly if necessary.
Flow Control Valve Inspection
Check flow control valve and spring for damage. Replace oil pump assembly if necessary.
INSPECTION AFTER ASSEMBLY
Relief Oil Pressure
CAUTION:
Make sure that belt tension is normal before starting the following procedure.
SGIA0989E
SST843A
Revision: 2010 May2011 QX56

POWER STEERING OIL PUMPST-53
< REMOVAL AND INSTALLATION >
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1. Connect the oil pressure gauge [SST: KV48103500 (J-26357)] and the oil pressure gauge adapter [SST: KV48102500 (J-
33914)] between oil pump discharge connector and high-pres-
sure hose. Bleed air from the hydraulic circuit while opening
valve fully. Refer to ST-30, "
Inspection".
2. Start engine. Run engine until oil temperature reaches 50 to 80°C (122 to 176 °F).
CAUTION:
 Leave the valve of the oil pressure gauge fully open while
starting and running engine. If engine is started with the
valve closed, the hydraulic pressure in oil pump goes up
to the relief pressure along with unusual increase of oil
temperature.
 Be sure to keep hose clear of belts and other parts when engine is started.
3. Fully close the oil pressure gauge valve with engine at idle and measure the relief oil pressure.
CAUTION:
Never keep valve closed for 10 seconds or longer.
4. Open the valve slowly after measuring. Repair oil pump if the relief oil pressure is outside the standard. Refer to ST-50, "
Disassembly and Assembly".
5. Disconnect the oil pressure gauge from hydraulic circuit.
6. When installing eye bolt (1) and copper washer (2) to oil pump (3), refer to the figure.
CAUTION:
 Never reuse copper washers.
 Apply power steering fluid to around copper washer, theninstall eye bolt.
 Install eye bolt with eye join t (assembled to high pressure
hose) (B) protrusion (A) facing with pump side cutout, and
then tighten it to the specifi ed torque after tightening by
hand. Refer to ST-54, "
Exploded View".
 Securely insert harness connector to pressure sensor.
7. Check fluid level, fluid leakage and air bleeding hydraulic sys- tem after the installation. Refer to ST-30, "
Inspection".
Relief oil pressure : Refer to
ST-58, "
Relief Oil Pres-
sure".
SGIA1225E
JSGIA0452ZZ
Revision: 2010 May2011 QX56

ST-54
< REMOVAL AND INSTALLATION >
HYDRAULIC LINE
HYDRAULIC LINE
Exploded ViewINFOID:0000000006225615
Engine speed sensitive type
JPGIA0096GB
1. Reservoir tank bracket 2. Reservoir tank 3. Clamp
4. Suction hose 5. Return hose 6. Eye bolt
7. Copper washer 8. Pressure sensor 9. Oil cooler
10. High pressure piping 11. Low pressure piping 12. Steering gear assembly
A. To power steering oil pump suction hose.
B. To power steering oil pump.
Refer to GI-4, "
Components" for symbols in the figure.
Revision: 2010 May2011 QX56

HYDRAULIC LINEST-55
< REMOVAL AND INSTALLATION >
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Vehicle speed sensitive type
JPGIA0074GB
1. Reservoir tank bracket 2. Reservoir tank 3. Clamp
4. Suction hose 5. Return hose 6. Eye bolt
7. Copper washer 8. Pressure sensor 9. Oil cooler
10. High pressure piping 11. Low pressure piping 12. Steering gear assembly
A. To power steering oil pump suction hose.
B. To power steering oil pump.
Refer to GI-4, "
Components" for symbols in the figure.
Revision: 2010 May2011 QX56

STC-1
STEERING
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SECTION STC
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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.
Revision: 2010 May2011 QX56