wheel INFINITI QX56 2011 Factory Service Manual

STC-1
STEERING
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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.
Revision: 2010 May2011 QX56

PRECAUTIONSSTC-3
< PRECAUTION >
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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
JSGIA0021GB
JPGIB0022GB
Revision: 2010 May2011 QX56

STC-22
< SYMPTOM DIAGNOSIS >
UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)
SYMPTOM DIAGNOSIS
UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIA-
TION)
Description INFOID:0000000006256131
 Hard steering when fully turning the steering wheel.
 Light steering when driving at a high speed.
Diagnosis Procedure INFOID:0000000006256132
1.CHECK SYSTEM FOR POWER SUPPLY AND GROUND
Perform trouble diagnosis for power supply and ground. Refer to STC-14, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace error-detected parts.
2.CHECK SYSTEM FOR VEHICLE SPEED SIGNAL
Perform trouble diagnosis for vehicle speed signal. Refer to STC-20, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace error-detected parts.
3.CHECK SYSTEM FOR ENGINE SPEED SIGNAL
Perform trouble diagnosis for engine speed signal. Refer to STC-18, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair or replace error-detected parts.
4.CHECK SYSTEM FOR POWER STEERING SOLENOID VALVE
Perform trouble diagnosis for power steering solenoid valve. Refer to STC-16, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> Perform the symptom diagnosis for the steering system. Refer to ST-29, "NVH Troubleshooting
Chart".
NO >> Repair or replace error-detected parts.
Revision: 2010 May2011 QX56

STR-1
ENGINE
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SECTION STR
A
STR
N
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CONTENTS
STARTING 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
PREPARATION ............................................4
PREPARATION .............................................. .....4
Special Service Tools .......................................... ......4
Commercial Service Tools ........................................4
SYSTEM DESCRIPTION ..............................5
COMPONENT PARTS ................................... .....5
Component Parts Location .................................. ......5
Component Description ............................................5
SYSTEM ..............................................................6
System Diagram .................................................. ......6
System Description ...................................................6
WIRING DIAGRAM .......................................7
STARTING SYSTEM ...................................... .....7
Wiring Diagram ................................................... ......7
BASIC INSPECTION ...................................11
DIAGNOSIS AND REPAIR WORKFLOW ........11
Work Flow ............................................................ ....11
DTC/CIRCUIT DIAGNOSIS .........................14
B TERMINAL CIRCUIT .....................................14
Diagnosis Procedure ........................................... ....14
S CONNECTOR CIRCUIT .................................15
Diagnosis Procedure ...............................................15
SYMPTOM DIAGNOSIS ..............................16
STARTING SYSTEM .........................................16
Symptom Table ................................................... ....16
REMOVAL AND INSTALLATION ...............17
STARTER MOTOR ...........................................17
Exploded View ..................................................... ....17
Removal and Installation .........................................18
Inspection ................................................................18
SERVICE DATA AND SPECIFICATIONS
(SDS) ............... .............................................
20
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
20
Starter Motor .......................................................
Revision: 2010 May2011 QX56

STR-2
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006275515
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:0000000006275516
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

PRECAUTIONSSTR-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

SYSTEMTM-45
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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 Transmit required output signals to the respective solenoids.
A/T CONTROL SYSTEM : Fail-SafeINFOID:0000000006226769
TCM has the electrical fail-safe mode. The mode is divi ded into a maximum of 3 phases (1st fail-safe, 2nd fail-
safe and final fail-safe) and functions so that the operat ion can be continued even if the signal circuit of the
main electronically controlled input/output parts is damaged.
Even if the electronic circuit is normal, the fail-safe mode may start under special conditions (such as when the
brake pedal is depressed suddenly from a hard wheel spin st atus to stop the rotation of wheels). In this case,
turn the ignition switch OFF and back to ON after 5 seconds to resume the normal shift pattern.
Consequently, the customer's vehicle may already return to the normal condition. Refer to TM-88, "
Diagnosis
Flow".
FAIL-SAFE FUNCTION
1st Fail-SafeThe mode that the vehicle can stop safely, to prompt the driver to stop if the malfunction occurs and to shift to
2nd fail-safe early. It shifts to 2nd fail-safe or final fail-safe after the vehicle stopped.
2nd Fail-Safe The mode that the vehicle shifts to final fail-safe without changing the behavior, by identifying the malfunction-
ing parts in the condition that the driving force required for the driving is secured.
Final Fail-Safe  Selects the shifting pattern that the malfunctioning parts identified at 1st fail-safe and 2nd fail-safe are not
used, and then secure the driving force that is required for the driving.
 The mode that the shifting performance does not decrease by normal shift control.
DTC Veh ic le
condition Vehicle behavior for 1st fail-safe Vehicle behavior for 2nd fail-safe Vehicle behavior for final fail-safe
P0615 — Starter is disabled — Starter is disabled
P0705 —  Fixed in the “D” position (The
shifting can be performed)
 30 km/h (19MPH) or less
 Lock-up is prohibited
 The shifting between the gears of 3 - 4 - 5 - 6 - 7 can be per-
formed
 Manual mode is prohibited
 Shift position indicator is switched OFF
 Starter relay is switched OFF (starter is disabled)
 Back-up lamp is OFF
 Large shift shock — Fixed in the “D” position (The
shifting can be performed)
 30 km/h (19 MPH) or less
 Lock-up is prohibited
 The shifting between the gears of 3 - 4 - 5 - 6 - 7 can be per-
formed
 Manual mode is prohibited
 Shift position indicator is switched OFF
 Starter relay is switched OFF (starter is disabled)
 Back-up lamp is OFF
 Large shift shock
P0710 Between
the gears of 1 - 2 - 3  The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited —
 The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited
Between
the gears of 4 - 5 - 6 - 7  Fix the gear while driving
 Manual mode is prohibited
—
P0717 Between
the gears of
1 - 2 - 3  The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited —
 The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited
Between
the gears of 4 - 5 - 6 - 7  Fix the gear while driving
 Manual mode is prohibited
—
Revision: 2010 May2011 QX56

TM-74
< ECU DIAGNOSIS INFORMATION >[7AT: RE7R01B]
TCM
Fail-Safe
INFOID:0000000006226783
TCM has the electrical fail-safe mode. The mode is divi ded into a maximum of 3 phases (1st fail-safe, 2nd fail-
safe and final fail-safe) and functions so that the operat ion can be continued even if the signal circuit of the
main electronically controll ed input/output parts is damaged.
Even if the electronic circuit is normal, the fail-safe mode may start under special conditions (such as when the
brake pedal is depressed suddenly from a hard wheel spin status to stop the rotation of wheels). In this case,
turn the ignition switch OFF and back to ON after 5 seconds to resume the normal shift pattern.
Consequently, the customer's vehicle may already return to the normal condition. Refer to TM-88, "
Diagnosis
Flow".
FAIL-SAFE FUNCTION
3
(L) —CAN-H
Input/
Output ——
4
(SB) —K-line Input/
Output ——
5
(B) Ground Ground Output Always 0 V
6
(V) Ground Power supply Input Ignition switch ON Battery voltage
Ignition switch OFF 0 V
7
(R) Ground Back-up lamp relay Input Ignition switch ON Selector lever in
“R” position. 0 V
Selector lever in other than
above. Battery voltage
8
(P) —CAN-L Input/
Output ——
9
(BR) Ground Starter relay Output Ignition switch ON Selector lever in “N” and “P” po-
sitions.
Battery voltage
Selector lever in other than
above. 0 V
10
(B) Ground Ground Output Always 0 V
Te r m i n a l
(Wire color) Description
Condition Value (Approx.)
+ −Signal name Input/
Output
1st Fail-Safe The mode that the vehicle can stop safely, to prompt the driver to stop if the malfunction occurs and to shift to
2nd fail-safe early. It shifts to 2nd fail-safe or final fail-safe after the vehicle stopped.
2nd Fail-Safe The mode that the vehicle shifts to final fail-safe without changing the behavior, by identifying the malfunction-
ing parts in the condition that the driving force required for the driving is secured.
Final Fail-Safe  Selects the shifting pattern that the malfunctioning parts identified at 1st fail-safe and 2nd fail-safe are not
used, and then secure the driving forc e that is required for the driving.
 The mode that the shifting performance does not decrease by normal shift control.
Revision: 2010 May2011 QX56