torque INFINITI QX56 2011 Factory Service Manual

SYSTEMTM-47
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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A/T CONTROL SYSTEM : Protection ControlINFOID:0000000006226770
The TCM becomes the protection control status temporar ily to protect the safety when the safety of TCM and
transmission is lost. It automatically returns to the normal status if the safety is secured.
The TCM has the following protection control.
REVERSE INHIBIT CONTROL
Intercepts the torque transmission and shift to the neutral stat us if the selector lever is shifted to “R” position
while the vehicle moves forward at the vehicle speed 10 km/h (7 MPH) or more.
1ST ENGINE BRAKE PROTECTION CONTROL
Controls the engine brake so as not to make effective by turning the front brake solenoid output to OFF when
each solenoid becomes the electricity pattern of 1st engine brake during driving at the vehicle speed 25 km/h
or more in any positions other than “R” position and 1GR.
TCM HIGH TEMPERATURE PROTECTION CONTROL
Limit the accelerator opening and forcibly control the vehi cle to the low torque driving when the electronic sub-
strate in TCM reaches the high temperature.
P1730 —  Neutral
 Manual mode is prohibited  The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited Locks in 1GR
 The shifting between the gears
of 2 - 3 - 4 can be performed
 The shifting between the gears
of 3 - 4 can be performed
 The shifting between the gears of 4 - 5 - 6 can be performed
 Manual mode is prohibited
P1815 — Manual mode is prohibited — Manual mode is prohibited
U0300
U1000 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
 Line pressure is set to the maxi-
mum hydraulic pressure
 Manual mode is prohibited
Between
the gears of 4 - 5 - 6 - 7  Fix the gear at driving
 Manual mode is prohibited
—
P0720 and
P1721 — Locks in 5GR — Locks in 5GR
DTC
Veh ic le
condition Vehicle behavior for 1st fail-safe Vehicle behavior for 2nd fail-safe Vehicle behavior for final fail-safe
Malfunction detection condition Vehicle speed: 10 km/h (7 MPH) or more
Control at malfunction Neutral
Normal return condition  Vehicle speed: 8 km/h (5 MPH) or less
and
 Engine speed: 2,200 rpm or less
Vehicle behavior  The torque transmission cannot be performed
 There is a shock just before a vehicle stop
Malfunction detection condition Select lever and gear: Any position other than “R” position and 1GR
and
 Vehicle speed: More than 25 km/h (16 MPH)
Control at malfunction Front brake solenoid output signal; OFF
Normal return condition Other than detection condition of malfunction
Vehicle behavior Does not exist
Revision: 2010 May2011 QX56

TM-48
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
LINE PRESSURE CONTROL
LINE PRESSURE CONTROL : System DiagramINFOID:0000000006226771
LINE PRESSURE CONTROL : System DescriptionINFOID:0000000006226772
 When an engine and A/T integrated control signal (engine
torque) equivalent to the engine drive force is
transmitted from the ECM to the TCM, the TC M controls the line pressure solenoid valve.
This line pressure solenoid controls the pressure regul ator valve as the signal pressure and adjusts the pres-
sure of the operating oil discharged from the oil pump to the line pressure most appropriate to the driving
state.
 The TCM has stored in memory a number of patterns fo r the optimum line pressure characteristic for the
driving state.
 In order to obtain the most appropriate line pressure char acteristic to meet the current driving state, the TCM
controls the line pressure solenoid current value and thus controls the line pressure.
Normal Control
Each clutch is adjusted to the necessary pressure to match the
engine drive force.
Back-up Control (Engine Brake)
Malfunction detection conditionTCM electronic substrate temperature
145
°C (293 °F) and 120 seconds
or
150 °C (302 °F)
Control at malfunction Accelerator opening: 0.5/8 or less
Normal return condition  TCM electronic substrate temperature: Less than 140
°C (284 °F)
and
 Vehicle speed: 5 km/h (3 MPH) or less
Vehicle behavior Accelerator opening: output torque of approximately 0.5/8
JSDIA1345GB
PCIA0008E
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

TM-50
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
SHIFT CHANGE CONTROL : System Diagram
INFOID:0000000006226773
SHIFT CHANGE CONTROL : System DescriptionINFOID:0000000006226774
Input/Output Signal Chart
Item Signal TCM function Actuator
Input speed sensor 1, 2 Input speed
Shift change control High and low reverse
clutch solenoid valve
 Direct clutch solenoid
valve
 Input clutch solenoid valve
 Low brake solenoid valve
 2346 brake solenoid valve
 Front brake solenoid valve
 Torque converter clutch so- lenoid valve
 Line pressure solenoid valve
 Anti-interlock solenoid valve
Output speed sensor Vehicle speed
A/T fluid temperature sensor ATF temperature
ECM
Engine speed signal*
Accelerator pedal position signal*
Closed throttle position signal*
Engine and A/T integrated control signal
(Engine torque)*
BCM Stop lamp switch signal*
JSDIA1659GB
Revision: 2010 May2011 QX56

SYSTEMTM-51
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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*: This signal is transmitted via communication line.
The clutch pressure control solenoid is controlled by the signals from the switches and sensors. Thus, the
clutch pressure is adjusted to be appropriate to t he engine load state and vehicle driving state. It becomes
possible to finely control the clutch hydraulic pressu re with high precision and a smoother shift change charac-
teristic is attained.
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
Shift Change System Diagram
*1: Full phase real-time feedback control monitors move ment of gear ratio at gear change, and controls oil
pressure in real-time to achieve the best gear ratio.
BLIPPING CONTROL
This system makes transmission clutch engage readily by controlling (synchronizing) engine revolution
according to the (calculation of) engine revolution after shifting down.
 “BLIPPING CONTROL” functions.
- When downshifting by accelerator pedal depression.
- When downshifting by the manual mode.
PCIA0012E
PCIA0013E
JSDIA0826GB
Revision: 2010 May2011 QX56

TM-52
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
 TCM selects “BLIPPING CONTROL”
or “NORMAL SHIFT CONTROL” according to the gear position, the
selector lever position, the engine torque and the speed when accelerating by pedal depression.
 Engine speed control demand signal is transmitted from TCM to ECM under “BLIPPING CONTROL”.
 ECM synchronizes the engine speed according to the engine speed control demand signal.
Downshifting by accelerator pedal depression
Downshifting by the manual mode
IDLE NEUTRAL CONTROL
JSDIA0815GB
JSDIA0817GB
Revision: 2010 May2011 QX56

SYSTEMTM-55
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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Input/Output Signal Chart
*: This signal is transmitted via CAN communication line.
 When driving on an up/down slope ASC judges up/down slope according to engine torque data transmitted from the ECM and vehicle speed.
Fixing at 4GR, 5GR or 6GR on an up-slope prevents sh ift hunting and controls the vehicle to gain optimum
driving force. On a down-slope, automatic shift-down to 4GR, 5GR or 6GR controls to gain optimum engine
brake.
 When driving on a curve TCM receives the side G sensor signal from the ABS ac tuator and electric unit (control unit). It locks to 4GR,
5GR or 6GR position in moderate cornering or to 3G R position in sharp cornering based on this signal. This
prevents any upshift and kickdown during corner ing, maintaining smooth vehicle travel.
To w M o d e
 High driving torque is required for towing a heavy load. The tow mode enables torque-oriented driving by
changing the shift schedule to that of delaying A/T gear shift timing (compared to normal driving).
 TCM receives tow mode switch signal from combination meter via CAN communication. The tow mode turns ON when TCM receives the signal. TCM transmits a tow mode indicator lamp signal to the combination
meter via CAN communication to turn ON the tow mode indicator lamp mounted in the combination meter.
MANUAL MODE
Item Signal TCM function Actuator
Input speed sensor 1, 2 Input speed
ASC (Adaptive shift control)  High and low reverse
clutch solenoid valve
 Direct clutch solenoid valve
 Input clutch solenoid valve
 Low brake solenoid valve
 2346 brake solenoid valve
 Front brake solenoid valve
 Torque converter clutch so- lenoid valve
 Line pressure solenoid valve
 Anti-interlock solenoid
valve
Output speed sensor Vehicle speed
A/T fluid temperature sensor ATF temperature
ECM
Engine speed signal*
Accelerator pedal position signal*
Closed throttle position signal*
Engine and A/T integrated control signal
(engine torque)*
ABS actuator and electric unit
(control unit) Side G sensor signal*
BCM Stop lamp switch signal*
Combination meter Tow mode switch signal*
JSDIA1362GB
Revision: 2010 May2011 QX56

TM-56
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
Input/Output Signal Chart
*: This signal is transmitted via CAN communication line.
 The TCM receives the manual mode signal, non-manual mode signal, manual mode shift up signal and
manual mode shift down signal from combination meter via CAN communication line. The TCM shifts shift
pattern control to the manual mode based on these signal s, and then shifts the A/T by operating each sole-
noid valve according to the shift operation of the driver.
 The TCM prohibits the manual mode while being in fail-safe mode due to an A/T malfunction, etc. Refer to TM-74, "
Fail-Safe".
Manual Mode Information
 The TCM transmits the manual mode shift refusal signal to the combination meter if the TCM refuses the
transmission from the driving status of vehicle when the selector lever shifts to “UP (+ side)” or “DOWN (−
side)” side. The combination meter blinks shift indicator on the combination meter and sounds the buzzer to
indicate the driver that the shifting is not performed when receiving this signal. However, the TCM does not
transmit the manual mode shift refusal signal in the conditions as per the following.
- When the selector lever shifts to “DOWN ( − side)” side in 1GR.
- When the selector lever shifts to “UP (+ side)” side in 7GR.
LOCK-UP CONTROL
LOCK-UP CONTROL : System DiagramINFOID:0000000006226777
LOCK-UP CONTROL : System DescriptionINFOID:0000000006226778
 The torque converter clutch piston in the torque conv erter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
 Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
 The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid
valve, which is controlled by a signal from TCM, and the torque converter clutch control valve engages or
releases the torque converter clutch piston.
Item Signal TCM function Actuator
Output speed sensor Vehicle speed
Manual mode High and low reverse clutch
solenoid valve
 Direct clutch solenoid valve
 Input clutch solenoid valve
 Low brake solenoid valve
 2346 brake solenoid valve
 Front brake solenoid valve
 Torque converter clutch sole- noid valve
 Line pressure solenoid valve
 Anti-interlock solenoid valve
A/T fluid temperature sensor ATF temperature
ECM
Engine speed signal*
Accelerator pedal position sig-
nal*
Combination meter Manual mode signal*
Non-manual mode signal*
Manual mode shift up signal*
Manual mode shift down signal*
JSDIA1350GB
Revision: 2010 May2011 QX56

SYSTEMTM-57
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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O PLock-up Operation Condition Table
Lock-up released
 In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
in this way, the torque converter clutch piston is not coupled.
Lock-up Applied
 In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the
torque converter clutch solenoid and lock-up apply pressure is generated.
In this way, the torque converter clutch piston is pressed and coupled.
Smooth Lock-up Control
When shifting from the lock-up released state to the lock- up applied state, the current output to the torque con-
verter clutch solenoid is controlled with the TCM. In this way, when shifting to the lock-up applied state, the
torque converter clutch is temporarily set to the half-clutched state to reduce the shock.
Half-clutched State The current output from the TCM to the torque converte r clutch solenoid is varied to steadily increase the
torque converter clutch solenoid pressure.
In this way, the lock-up apply pressure gradually rises and while the torque converter clutch piston is put into
half-clutched states, the torque conv erter clutch piston operating pressure is increased and the coupling is
completed smoothly.
Slip Lock-up Control In the slip region, the torque converter clutch solenoid current is controlled with the TCM to put it into the
half-clutched state. This absorbs the engine tor que fluctuation and lock-up operates from low speed.
This raises the fuel efficiency fo r 2GR, 3GR, 4GR, 5GR, 6GR and 7GR.
A/T SHIFT LOCK SYSTEM
JSDIA0847GB
Selector lever “D” position “M” position
Gear position 765432765432
Lock-up×––––– ××××××
Slip lock-up ××××××××××××
Revision: 2010 May2011 QX56

TM-62
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
DIAGNOSIS SYSTEM (TCM)
INPUT SPEED (rpm) X X Displays the input speed calculated from front
sun gear revolution and front carrier revolution.
F SUN GR REV (rpm) — — Displays the front sun gear revolution calculat-
ed from the pulse signal of input speed sensor
1.
F CARR GR REV (rpm) — — Displays the front carrier gear revolution calcu-
lated from the pulse signal of input speed sen-
sor 2.
ENGINE SPEED (rpm) X X Displays the engine speed received via CAN
communication.
TC SLIP SPEED (rpm) — X Displays the revolution difference between in-
put speed and engine speed.
ACCELE POSI (0.0/8) X — Displays the accelerator position estimated val-
ue received via CAN communication.
THROTTLE POSI (0.0/8) X X Displays the throttle position received via CAN
communication.
ATF TEMP 1 ( °C or °F) X X Displays the ATF temperature of oil pan calcu-
lated from the signal voltage of A/T fluid tem-
perature sensor.
ATF TEMP 2 ( °C or °F) X X Displays the ATF temperature estimated value
of torque converter outlet calculated from the
signal voltage of A/T fluid temperature sensor.
ATF TEMP SE 1 (V) — — Displays the signal voltage of A/T fluid temper-
ature sensor.
BATTERY VOLT (V) X — Displays the power supply voltage of TCM.
LINE PRES SOL (A) — X Displays the command current from TCM to the
line pressure solenoid.
TCC SOLENOID (A) — X Displays the command current from TCM to the
torque converter clutch solenoid.
L/B SOLENOID (A) — X Displays the command current from TCM to the
low brake solenoid.
FR/B SOLENOID (A) — X Displays the command current from TCM to the
front brake solenoid.
HLR/C SOL (A) — X Displays the command current from TCM to the
high and low reverse clutch solenoid.
I/C SOLENOID (A) — X Displays the command current from TCM to the
input clutch solenoid.
D/C SOLENOID (A) — X Displays the command current from TCM to the
direct clutch solenoid.
2346/B SOL (A) — X Displays the command current from TCM to the
2346 brake solenoid.
L/P SOL MON (A) — — Monitors the command current from TCM to the
line pressure solenoid, and displays the moni-
tor value.
TCC SOL MON (A) — — Monitors the command current from TCM to the
torque converter clutch solenoid, and displays
the monitor value.
L/B SOL MON (A) — — Monitors the command current from TCM to the
low brake solenoid, and displays the monitor
value.
Monitored item (Unit)
Monitor Item Selection
Remarks
ECU IN-
PUT SIG- NALS MAIN SIG-
NALS SELEC-
TION
FROM ITEM
Revision: 2010 May2011 QX56