2011 INFINITI QX56 transmission

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

STRUCTURE AND OPERATIONTM-43
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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 When A/T fluid temperature rises [to approximately 100 °C
(212 °F)], bypass valve closes and allows ATF to flow into cooler
core. ATF flowing into cooler core is cooled by air stream caused
by vehicle travel and returned to transmission.
JSDIA1816GB
Revision: 2010 May2011 QX56

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-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

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

SYSTEMTM-53
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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Input/Output Signal Chart
*: This signal is transmitted via communication line.
The TCM activates low brake solenoid valve and controls t he low brake oil pressure to the low pressure level
if the driver does not intend to start the vehicle while the vehicle is being stopped in the “D” position. Therefore,
the low brake is in the release (slip) status and the pow er transmission route of A/T is the same status as the
“N” position. This can decrease the engine load and im proves the fuel economy because the drive force of
engine is not transmitted to the output shaft of A/T.
Idle Neutral Contro l Start Condition
Idle neutral control starts when all of the following c onditions are satisfied. However, the control ends when
any one of the following conditions becomes insufficient during idle neutral control.
NOTE:
The idle neutral control is terminated or prohibited when the TCM and ECM detect that the vehicle is in any of
the conditions as per the following.
 Engine cooling water temperature and A/T fluid temperature are below or above a prescribed temperature.
 A/T malfunction occurs.
 DTC is detected.
 Fail-safe mode activates.
 Idle neutral control is performed continuously for a certain period of time.
Idle Neutral Contro l Resume Condition
Idle neutral control can be resumed when its start condition is fulfilled after any of the following operations is
performed (unless a malfunction occurs in the vehicle).
 After driving at more than a prescribed speed.
 When idle neutral control start conditions are fulfilled for a certain period of time.
SHIFT PATTERN CONTROL
Item Signal
TCM function Actuator
Each sensor, switch and
control unit ⇒ TCM TCM
⇒ ECM ECM ⇒ TCM
Input speed sensor 1, 2 Input speed
N idle instruction
signal (Standby sig- nal)* N idle instruction
signal (Start signal)* Idle neutral con-
trol Low brake sole-
noid valve
Output speed sensor Output shaft revolution
A/T fluid temperature
sensor
ATF temperature
Transmission range
switch Selector lever position
ECM Engine speed signal*
Accelerator pedal posi-
tion signal*
Throttle position signal*
BCM Stop lamp switch signal*
Turn indicator signal*
ABS actuator electric
unit (control unit) Pressure sensor signal*
Decel G sensor signal*
Combination meter Vehicle speed signal*
Driving location : Level road and gentle slope
Selector lever position : “D” position
Vehicle speed : 0 km/h (0 MPH)
Accelerator pedal opening : 0.0 / 8
Brake pedal : Depress
Engine speed : Idle speed
Snow mode switch : OFF
Turn signal lamp and ha zard warning lamp : OFF
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

DIAGNOSIS SYSTEM (TCM)TM-61
< SYSTEM DESCRIPTION > [7AT: RE7R01B]
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DIAGNOSIS SYSTEM (TCM)
CONSULT-III Function (TRANSMISSION)INFOID:0000000006226781
CONSULT-III APPLICATION ITEMS
*: Although “Function Test” and “Special Function” are selectable, do not use its.
WORK SUPPORT
SELF DIAGNOSTIC RESULTS
Refer to TM-78, "DTC Index".
IGN Counter
The IGN counter is indicated in Fr eeze frame data (FFD) and indicates the number of times that the ignition
switch is turned ON after returning to the normal state from DTC.
 CAN malfunction
- The number is 0 when a malfunction is detected now.
- The number increases like 1 → 2 → 3...38 → 39 after returning to the normal condition whenever ignition
switch OFF → ON.
- The number is fixed to 39 until the self-di agnosis results are erased if it is over 39.
 Other than CAN malfunction
- The number is 0 when a malfunction is detected now.
- The number increases like 1 → 2 → 3...254 → 255 after returning to the normal condition whenever ignition
switch OFF → ON.
- The number is fixed to255 until the self-diagno sis results are erased if it is over 255.
DATA MONITOR
X: Standard, —: Not applicable, : Option
Diagnostic test mode Function
Work Support This mode enables a technician to adjust some devices faster and more accurately.
Self Diagnostic Results Retrieve DTC from ECU and display diagnostic items.
Data Monitor Monitor the input/output signal of the control unit in real time.
CAN Diagnosis This mode displays a network diagnosis result about CAN by a diagram.
CAN Diagnostic Support
Monitor It monitors the status of CAN communication.
DTC & SRT confirmation The status of system monitoring tests and the self-diagnosis status/result can be confirmed.
ECU Identification Display the ECU identification number (part number etc.) of the selected system.
Function Test* This mode can show results of self-diagnosis of ECU with either “OK” or “NG”. For engine, more prac-
tical tests regarding sensors/switches and/or actuators are available.
Special Function* Other results or histories, etc. that are recorded in ECU are displayed.
Item name Description
G SENSOR CALIBRATION Calibrates G sensor.
Monitored item (Unit) Monitor Item Selection
Remarks
ECU IN-
PUT SIG- NALS MAIN SIG-
NALS SELEC-
TION
FROM
ITEM
VHCL/S SE-A/T (km/h or mph) X X Displays the vehicle speed calculated by the
TCM from the output shaft revolution.
ESTM VSP SIG (km/h or mph) X — Displays the vehicle speed signal received via
CAN communication.
OUTPUT REV (rpm) X X Displays the output speed calculated from the
pulse signal of output speed sensor.
Revision: 2010 May2011 QX56