lock INFINITI QX56 2011 Factory Service Manual

TM-44
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
SYSTEM
A/T CONTROL SYSTEM
A/T CONTROL SYSTEM : System DiagramINFOID:0000000006226767
A/T CONTROL SYSTEM : System DescriptionINFOID:0000000006226768
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
 The A/T senses vehicle operating conditions through vari
ous sensors or signals. It always controls the opti-
mum shift position and reduces shifting and lock-up shocks.
 Receive input signals transmitted from various switches and sensors.
 Determine required line pressure, shifting point, lock-up operation, etc.
JSDIA1853GB
Sensor (or signal)
⇒TCM function
⇒Actuator
Transmission range switch
Accelerator pedal position signal
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Output speed sensor
Vehicle speed signal
Manual mode switch signal
Stop lamp switch signal
Input speed sensor 1, 2
Yaw rate/side/decel G sensor
Tow mode switch signal Line pressure control (
TM-48
)
Shift change control ( TM-50
)
Shift pattern control ( TM-54
)
Lock-up control ( TM-56
)
Fail-safe control ( TM-45
)
Self-diagnosis ( TM-61
)
CONSULT-III communication line ( TM-61
)
CAN communication line ( TM-103
)Input clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch solenoid valve
Low brake solenoid valve
Torque converter clutch solenoid valve
Line pressure solenoid valve
Anti-interlock solenoid valve
2346 brake solenoid valve
A/T CHECK indicator lamp
Tow mode indicator lamp
Shift position indicator
Back-up lamp relay
Starter relay
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-46
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
P0720Between
the gears of 1 - 2 - 3  Only downshift can be per-
formed
 Manual mode is prohibited
 A vehicle speed signal from the combination mete r is regarded
as an effective signal —
 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 at driving
 Manual mode is prohibited
 A vehicle speed signal from the
combination mete r is regarded
as an effective signal —
P0729
P0731
P0732
P0733
P0734
P0735
P1734 Neutral
malfunction
between
the gears of
1 - 2 - 3 and
7
Locks in 4GR
 Manual mode is prohibited
Neutral
— Locks in 1GR
 The shifting between the gears
of 1 - 2 can be performed
 The shifting between the gears
of 1 - 2 - 3 can be performed
 The shifting between the gears of 4 - 5 - 6 can be performed
 Manual mode is prohibited
Other than
the above  Driving with the gear ratio be-
tween 1GR and 2GR
 Driving with the gear ratio be-
tween 2GR and 3GR
Locks in 3GR
Locks in 4GR
 Fix the gear while driving
 Manual mode is prohibited
Neutral  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 1 - 2 can be performed
 The shifting between the gears of 1 - 2 - 3 can be performed
 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
P0730 —  Manual mode is prohibited
Neutral  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 1 - 2 can be performed
 The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited
P0740 —  Lock-up is prohibited
 Slip lock-up is prohibited —
 Lock-up is prohibited
 Slip lock-up is prohibited
P0744 —  Lock-up is prohibited
 Slip lock-up is prohibited — Lock-up is prohibited
 Slip lock-up is prohibited
P0750
P0775
P0795
P2713
P2722
P2731
P2807 —
 Locks in 2GR, 3GR, 4GR, 5GR,
6GR or 7GR
 Manual mode is prohibited — Locks in 1GR
 The shifting between the gears
of 1 - 2 - 3 can be performed
 The shifting between the gears
of 3 - 4 - 5 can be performed
 The shifting between the gears of 4 - 5 - 6 can be performed
 The shifting between the gears of 1 - 2 - 3 - 4 - 5 - 6 can be per-
formed
 Manual mode is prohibited
P0780 —  Manual mode is prohibited
Neutral
— The shifting between the gears
of 1 - 2 - 3 can be performed
 Manual mode is prohibited
P1705 —  Downshift when accelerator ped-
al is depressed is prohibited
 Upshift when accelerator pedal is released is prohibited
 Manual mode is prohibited  Downshift when accelerator ped-
al is depressed is prohibited
 Upshift when accelerator pedal is released is prohibited
 Manual mode is prohibited  Downshift when accelerator ped-
al is depressed is prohibited
 Upshift when accelerator pedal is released is prohibited
 Manual mode is prohibited
DTC
Vehicle
condition Vehicle behavior for 1st fail-safe Vehicle behavior for 2nd fail-safe Vehicle behavior for final fail-safe
Revision: 2010 May2011 QX56

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-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-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-58
< SYSTEM DESCRIPTION >[7AT: RE7R01B]
SYSTEM
A/T SHIFT LOCK SYSTEM : System Description
INFOID:0000000006226779
The selector lever cannot be shift ed from the “P” position unless the
brake pedal is depressed while the ignition switch is set to ON. The
shift lock is unlocked by turning the shift lock solenoid ON when the
ignition switch is set to ON, the park position switch is turned ON
(selector lever is in “P” position), and the stop lamp switch is turned
ON (brake pedal is depressed) as shown in the operation chart in the
figure. Therefore, the shift lock solenoid receives no ON signal and
the shift lock remains locked if all of the above conditions are not ful-
filled. (However, selector operation is allowed if the shift lock release
button is pressed.)
SHIFT LOCK OPERATION AT “P” POSITION
When Brake Pedal Is Not Depressed (No Selector Operation Allowed)
The shift lock solenoid (A) is turned OFF (not energized) and the
solenoid rod (B) is extended with the spring when the brake pedal is
not depressed (no selector operation allowed) with the ignition
switch ON.
The connecting lock lever (C) is located at the position shown in the
figure when the solenoid rod is extended. It prevents the movement
of the detent rod (D). For these r easons, the selector lever cannot be
shifted from the “P” position.
When Brake Pedal Is Depressed (Shift Operation Allowed)
The shift lock solenoid (A) is turned ON (energized) when the brake
pedal is depressed with the ignition switch ON. The solenoid rod (B)
is compressed by the electrom agnetic force. The connecting lock
lever (C) rotates when the solenoid is activated. Therefore, the
detent rod (D) can be moved. For these reasons, the selector lever
can be shifted to other positions.
“P” POSITION HOLD MECHANI SM (IGNITION SWITCH LOCK)
JPDIA0624GB
JPDIA0612ZZ
JPDIA0613ZZ
Revision: 2010 May2011 QX56

SYSTEMTM-59
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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The shift lock solenoid (A) is not energized when the ignition switch
is in any position other than ON. In this condition, the shift mecha-
nism is locked and “P” position is held. The operation cannot be per-
formed from “P” position if the brake pedal is depressed with the
ignition switch ON when the operation system of shift lock solenoid is
malfunctioning. However, the lock lever (B) is forcibly rotated and the
shift lock is released when the shift lock release button (C) is
pressed from above. Then the sele ctor operation from “P” position
can be performed.
CAUTION:
Use the shift lock release button only when the selector lever canno t be operated even if the brake
pedal is depressed with the ignition switch ON.
D : Detent rodJPDIA0614ZZ
Revision: 2010 May2011 QX56