ESP INFINITI QX56 2011 Factory Service Manual

STRUCTURE AND OPERATIONSCS-9
< SYSTEM DESCRIPTION > [HBMC]
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STRUCTURE AND OPERATION
Hydraulic Body-Moti on Control SystemINFOID:0000000006256001
Shock AbsorberINFOID:0000000006256002
The use of accumulator-generated pressure responsive to driving conditions or pressure generated by oil flow
to the upper/lower chamber improves the steering stabili ty at curving, in addition to the running performance
and a ride quality during off-road travel.
FRONT SIDE
Oil enters from oil inlet outlet hole (A) and flows into lower chamber (3) via outside oil path of cylinder inside.
Oil enters from oil inlet outlet hole (B) and flows into upper chamber (1). With the pressure difference between
oil flowed into the upper chamber and lower chamber, the piston (2) moves up and down and conveys a force
generated through this motion to the tires.
1. Middle tube assembly RH 2. Accumulator assembly RH 3. Front tube assembly A
4. Front tube assembly B 5. Accumulator assembly LH 6. PPMU pipe A
7. PPMU assembly 8. Middle tube assembly LH 9. PPMU pipe B
10. Rear tube assembly A 11. Rear tube assembly B
:Vehicle front
JSEIA0228ZZ
Revision: 2010 May2011 QX56

C1804 VHCL HEIGHT ADJ UPSCS-77
< DTC/CIRCUIT DIAGNOSIS > [AIR LEVELIZER CONTROL SYSTEM]
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C1804 VHCL HEIGHT ADJ UP
DTC LogicINFOID:0000000006256070
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Set vehicle in the unloaded vehicle status.
2. Start the engine and wait 150 seconds or more.
3. Perform “Self Diagnostic Result” in “E-SUS”.
Is
“C1804” detected ?
YES >> Go to SCS-77, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256071
1.CHECK APPEARANCE
Visually check for malfunction of suspension component s, damage of air chamber of rear shock absorber,
installation malfunction, or defo rmation of vehicle height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK AIR LEAK
Apply soapy water to air tube, connecting portions between air tube and each component, and air chamber of
rear shock absorber. Check for air leakage.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repaire or replace damaged parts.
3.CHECK AIR COMPRESSOR RELAY POWER SUPPLY
1. Turn ignition switch OFF.
2. Check 30A fuse (#I).
3. Disconnect air compressor relay connector.
4. Check voltage between air compressor relay harness connector and ground.
DTC Display item Malfunction detected condition Possible cause
C1804 VHCL HEIGHT ADJ UP The vehicle height is 15 mm (0.59 in) or more lower
than the reference height despite the output of air
compressor ON signal continuously for 120 seconds
by the air levelizer control module.  Harness or connector
Air compressor
 Air compressor relay
 Air levelizer control module
 Rear shock absorber (air cham-
ber)
 Vehicle height sensor
 Air tube
 Rear suspension component parts
 Overloaded
Revision: 2010 May2011 QX56

SCS-80
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
C1805 VHCL HE
IGHT ADJ DOWN
C1805 VHCL HEIGHT ADJ DOWN
DTC LogicINFOID:0000000006256074
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Start the engine and wait 150 seconds or more.
2. Perform “Self Diagnostic Result” in “E-SUS”.
Is
“C1805” detected ?
YES >> Go to SCS-80, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256075
1.CHECK APPEARANCE
Visually check for malfunction of suspension components, crush of air tube, installation malfunction, or defor-
mation of vehicle height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Perform “STANDARD VEHICLE HEIGHT SETTING”. Refer to SCS-67, "Work Procedure".
NO >> Repair or replace damaged part.
DTC Display item Malfunction detected condition Possible cause
C1805 VHCL HEIGHT ADJ DOWN The vehicle height is 15 mm (0.59 in) or more raise than
the reference height despite the output of exhaust sole-
noid ON signal continuously for 120 seconds by the air
levelizer control module.  Harness or connector
 Vehicle height sensor
Air compressor
(exhaust sole-
noid)
Air tube
 Rear suspension component
parts
Revision: 2010 May2011 QX56

SQUEAK AND RATTLE TROUBLE DIAGNOSESSE-99
< SYMPTOM DIAGNOSIS >
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SQUEAK AND RATTLE TROUBLE DIAGNOSES
Work FlowINFOID:0000000006219938
CUSTOMER INTERVIEW
Interview the customer if possible, to determine the conditions that exist when the noise occurs. Use the Diag-
nostic Worksheet during the interview to document t he facts and conditions when the noise occurs and any of
customer's comments; refer to SE-103, "
Diagnostic Worksheet". This information is necessary to duplicate the
conditions that exist when the noise occurs.
 The customer may not be able to provide a detailed description or the location of the noise. Attempt to obtain all the facts and conditions that exist when the noise occurs (or does not occur).
 If there is more than one noise in the vehicle, perform a diagnosis and repair the noise that the customer is
concerned about. This can be accomplished by performing a cruise test on the vehicle with the customer.
 After identifying the type of noise, isolate the noise in terms of its characteristics. The noise characteristics
are provided so the customer, service adviser and technician are all speaking the same language when
defining the noise.
 Squeak – (Like tennis shoes on a clean floor)
Squeak characteristics include the light contact/fast movement/brought on by road conditions/hard surfaces
= higher pitch noise/softer surfaces = lower pitch noises/edge to surface = chirping
 Creak – (Like walking on an old wooden floor)
Creak characteristics include firm contact/slow mo vement/twisting with a rotational movement/pitch depen-
dent on materials/often brought on by activity.
 Rattle – (Like shaking a baby rattle)
Rattle characteristics include the fast repeated contac t/vibration or similar movement/loose parts/missing
clip or fastener/incorrect clearance.
 Knock – (Like a knock on a door)
Knock characteristics include hollow sounding/someti mes repeating/often brought on by driver action.
 Tick – (Like a clock second hand) Tick characteristics include gentle contacting of li ght materials/loose components/can be caused by driver
action or road conditions.
 Thump – (Heavy, muffled knock noise) Thump characteristics include softer k nock/dead sound often brought on by activity.
 Buzz – (Like a bumblebee)
Buzz characteristics include high frequency rattle/firm contact.
 Often the degree of acceptable noise level will vary depending up on the person. A noise that a technician may judge as acceptable may be very irritating to the customer.
 Weather conditions, especially humidity and temperat ure, may have a great effect on noise level.
DUPLICATE THE NOISE AND TEST DRIVE
If possible, drive the vehicle with the customer until the noise is duplicated. Note any additional information on
the Diagnostic Worksheet regarding the conditions or lo cation of the noise. This information can be used to
duplicate the same conditions when the repair is reconfirmed.
SBT842
Revision: 2010 May2011 QX56

DIAGNOSIS AND REPAIR WORK FLOWSTC-13
< BASIC INSPECTION >
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BASIC INSPECTION
DIAGNOSIS AND REPAIR WORK FLOW
Work FlowINFOID:0000000006256124
DETAILED FLOW
1.COLLECT THE INFORMATION FROM THE CUSTOMER
It is also important to clarify customer complaints before inspection. First of all, reproduce symptoms and
understand them fully. Ask customer about his/her complaints carefully. In some cases, it is necessary to
check symptoms by driving vehicle with customer.
CAUTION:
Customers are not professional. It is danger ous to make an easy guess like “maybe the customer
means that...,” or “maybe the cu stomer mentions this symptom”.
>> GO TO 2.
2.CHECK THE STATUS
1. Power steering fluid leakage and check the power steering fluid level. Refer to ST-30, "
Inspection".
2. Check the drive belt tension. Refer to EM-20, "
Checking".
3. Check the power steering gear for damages, cracks and fluid leakage. Refer to ST-46, "
Inspection".
4. Check the relief oil pressure. Refer to ST-52, "
Inspection".
>> GO TO 3.
3.DIAGNOSIS CHART BY SYMPTOM
Perform the diagnosis by symptom. Refer to STC-22, "
Diagnosis Procedure".
>> GO TO 4.
4.FINAL CHECK
Check the input/output standard values for the power steering control unit.
Are the power steering control unit input/output values within standard ranges respectively?
YES >> INSPECTION END
NO >> GO TO 2.
Revision: 2010 May2011 QX56

TM-12
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
COMPONENT PARTS
A/T CONTROL SYSTEM : TCM
INFOID:0000000006226740
 The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The
TCM controls the A/T.
 The TCM is integral with the control valve assembly and built into the A/T assembly.
A/T CONTROL SYSTEM : Tr ansmission Range SwitchINFOID:0000000006226741
 The transmission range switch incorpor ates four contact switches. Each contact switch transmits an ON/
OFF signal to the TCM.
 The TCM judges a select lever position from a comb ination of ON/OFF signals transmitted from each con-
tact switch.
A/T CONTROL SYSTEM : Input Speed SensorINFOID:0000000006226742
The input speed sensor detects input shaft rpm (revolutions per minute). It is located on the input side of the A/
T. Monitors revolution of sensor 1 and sensor 2 for non-standard conditions.
A/T CONTROL SYSTEM : Output Speed SensorINFOID:0000000006226743
The output speed sensor detects the revolution of t he parking gear and emits a pulse signal. The pulse signal
is transmitted to the TCM which converts it into vehicle speed.
A/T CONTROL SYSTEM : A/T Fluid Temperature SensorINFOID:0000000006226744
The A/T fluid temperature sensor detects the A/T fluid temperature and transmits a signal to the TCM.
A/T CONTROL SYSTEM : Input Clutch Solenoid ValveINFOID:0000000006226745
 The Input clutch solenoid valve is controlled by the TCM in response to signals transmitted from the trans-
mission range switch, output speed sensor and accelerato r pedal position sensor. Gears will then be shifted
to the optimum position.
 The Input clutch solenoid valve controls the input cl utch control valve in response to a signal transmitted
from the TCM.
A/T CONTROL SYSTEM : Front Brake Solenoid ValveINFOID:0000000006226746
 The front brake solenoid valve is controlled by the TC M in response to signals transmitted from the transmis-
sion range switch, output speed sensor and accelerator pedal position sensor. Gears will then be shifted to
the optimum position.
 The front brake solenoid valve controls the front brak e control valve in response to a signal transmitted from
the TCM.
A/T CONTROL SYSTEM : Direc t Clutch Solenoid ValveINFOID:0000000006226747
 The direct clutch solenoid valve is controlled by t he TCM in response to signals transmitted from the trans-
mission range switch, output speed sensor and accelerato r pedal position sensor. Gears will then be shifted
to the optimum position.
 The direct clutch solenoid valve controls the direct clutch control valve in response to a signal transmitted
from the TCM.
Select lever position Transmission range switch
SW1 SW2 SW3 SW4
POFFOFFOFFOFF
RONOFFOFFON
NONONOFFOFF
D and M ONONONON
Revision: 2010 May2011 QX56

COMPONENT PARTSTM-13
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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A/T CONTROL SYSTEM : High and Lo w Reverse Clutch Solenoid ValveINFOID:0000000006226748
 The high and low reverse clutch solenoid valve is controlled by the TCM in response to signals transmitted
from the transmission range switch, output speed sens or and accelerator pedal position sensor. Gears will
then be shifted to the optimum position.
 The high and low reverse clutch solenoid valve controls the high and low reverse clutch control valve in response to a signal transmitted from the TCM.
A/T CONTROL SYSTEM : Lo w Brake Solenoid ValveINFOID:0000000006226749
 The low brake solenoid valve is controlled by the TC M in response to signals transmitted from the transmis-
sion range switch, output speed sensor and accelerator pedal position sensor. Gears will then be shifted to
the optimum position.
 The low brake solenoid valve controls the low brake control valve in response to a signal transmitted from
the TCM.
A/T CONTROL SYSTEM : Anti-interlock Solenoid ValveINFOID:0000000006226750
 Anti-interlock solenoid valve prevents the simultaneous activation of the input clutch and the low brake.
 The anti-interlock solenoid valve is an ON/OFF type solenoid valve.
A/T CONTROL SYSTEM : 2 346 Brake Solenoid ValveINFOID:0000000006226751
 The 2346 brake solenoid valve is controlled by the TC M in response to signals transmitted from the trans-
mission range switch, output speed sensor and accelera tor pedal position sensor. Gears will then be shifted
to the optimum position.
 The 2346 brake solenoid valve controls the 2346 brake c ontrol valve in response to a signal transmitted from
the TCM.
A/T CONTROL SYSTEM : Torque Co nverter Clutch Solenoid ValveINFOID:0000000006226752
The torque converter clutch solenoid va lve is activated, with the gear in D2, D3, D4, D5, D6, D7, M2, M3, M4,
M5, M6 and M7 by the TCM in response to signals tr ansmitted from the output speed sensor and accelerator
pedal position sensor. Torque converter clut ch piston operation will then be controlled.
A/T CONTROL SYSTEM : Line Pressure Solenoid ValveINFOID:0000000006226753
The line pressure solenoid valve regulates the oil pum p discharge pressure to suit the driving condition in
response to a signal transmitted from the TCM.
A/T CONTROL SYSTEM : Accele rator Pedal Position SensorINFOID:0000000006226754
 The accelerator pedal position sensor is installed on the upper end of the accelerator pedal assembly.
 The accelerator pedal position sensor detects the accelerator position.
 The accelerator pedal position sensor transform the a ccelerator pedal position into output voltage, and emit
the voltage signal to the ECM. Then, the TCM receives accelerator pedal position signal from the ECM via
CAN communication.
A/T CONTROL SYSTEM : Manual Mode SwitchINFOID:0000000006226755
 The manual mode switch [mode select switch and position se lect switch (shift-up/shift-down)] is installed in
the A/T shift selector assembly.
 The mode select switch detects the position (the main shift gate side or manual shift gate side) of the selec-
tor lever and transmits a manual mode signal or a not manual mode signal to the combination meter. Then,
the TCM receives a manual mode signal or non-manual mode signal from the combination meter.
 The position select switch (shift-up) detects that the se lector lever is shifted to the shift-up side of the manual
shift gate and transmits a manual mode shift up signal to the combination meter. Then, the TCM receives a
manual mode shift up signal from the combination meter.
 The position select switch (shift-down) detects that the selector lever is shifted to the shift-down side of the
manual shift gate and transmits a manual mode shift down signal to the combination meter. Then, the TCM
receives a manual mode shift down signal from the combination meter.
Revision: 2010 May2011 QX56

TM-42
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
STRUCTURE AND OPERATION
A/T FLUID COOLER SCHEMATIC
COMPONENT DESCRIPTION
A/T fluid warmer
 The A/T fluid warmer (1) is installed on the front part of cylinder
block of engine.
 When engine is started while engine and A/T are cold, engine cool-
ant temperature rises more quickly than A/T fluid temperature. A/T
fluid warmer is provided with two circuits for ATF and engine cool-
ant respectively so that warmed engine coolant warms ATF
quickly. This helps shorten A/T warming up time, improving fuel
economy.
 A cooling effect is obtained when A/T fluid temperature is high.
A/T fluid cooler (with bypass valve)
 A/T fluid cooler (1) is installed in the front of radiator (2) and con- denser (3).
 A/T fluid cooler is provided with a bypass valve that controls ATF
flow. Bypass valve operates by thermo wax and a return spring.
Bypass valve fully opens when A/T fluid temperature is approxi-
mately 90 °C (194 °F) and fully closes when A/T fluid temperature is
approximately 100 °C (212 °F).
 When A/T fluid temperature is low, the bypass valve is open. Most of ATF therefore returns to the transmission without flowing into the
cooler core that has larger flow resistance.
JSDIA1803GB
JSDIA1811ZZ
JSDIA1814ZZ
JSDIA1815GB
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

SYSTEMTM-49
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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When the select operation is performed during driving and the A/T is
shifted down, the line pressure is set according to the vehicle speed.
During Shift Change
The necessary and adequate line pressure for shift change is set.
For this reason, line pressure pattern setting corresponds to engine
torque and gearshift selection. Also, line pressure characteristic cor-
responds to engine speed, during engine brake operation.
At Low Fluid Temperature
When the A/T fluid temperature drops below the prescribed tempera-
ture, in order to speed up the action of each friction element, the line
pressure is set higher than the normal line pressure characteristic.
SHIFT CHANGE CONTROL
PCIA0009E
PCIA0010E
PCIA0011E
Revision: 2010 May2011 QX56