clutch INFINITI QX56 2010 Factory Service Manual

A/T CONTROL SYSTEMTM-21
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CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000005148511
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-4,
"System Description".
SENSORS (or SIGNALS)
⇒TCM
⇒ACTUATORS
Transmission range switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Output speed sensor
Vehicle speed signal
Stop lamp switch signal
Input speed sensor
1st position switch signal
4th position switch signal
ATF pressure switch 2 signal
Tow mode switch signal Shift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-III co
mmunication
line
Duet-EA control
CAN system Input clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch sole-
noid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Starter relay
Back-up lamp relay
JSDIA1315GB
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TM-22
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
Input/Output Signal of TCM
INFOID:0000000005148512
*1: Spare for output speed sensor
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: CAN comm unications
*5: Used as a condition for starting self-diagnostics; if self-diagnostics are not started, it is judged that there is some kin d of error.
*6: A/T fluid temperature sensor 2 does not have any function.
Line Pressure ControlINFOID:0000000005148513
• When an input torque signal equivalent to the engine drive force is sent from the ECM to the TCM, the TCM
controls the line pressure solenoid.
Control item Line
pres- sure
control Vehicle
speed
control S h i f t
control Lock-up
control Engine
brake
control Fail-safe
function (*3) Self-diag-
nostics
function
Input Accelerator pedal position signal
(*4)XXXXX X X
Output speed sensor X X X X X X
Vehicle speed signal
(*1) (*4)XXXX X
Closed throttle position signal
(*4)(*2) X (*2) X X (*2) X(*5) X
Wide open throttle position signal
(*4)(*2) X (*2) X (*2) X(*5) X
Input speed sensor 1 X XXX X
Input speed sensor 2
(for 4th speed only) XX X
X X
Engine speed signals
(*4)XX
Transmission range switch X X X X X X X
Stop lamp switch signal
(*4)XXX (*5) X
A/T fluid temperature sensors 1, 2 (*6) X X X X X X X
ASCD Operation signal
(*4)XXXX
Overdrive cancel sig-
nal
(*4)XXX
TCM power supply voltage signal X X X X X X
Output Direct clutch solenoid
X XX X
Input clutch solenoid X XX X
High and low reverse clutch solenoid X XX X
Front brake solenoid X XX X
Low coast brake solenoid (ATF pressure
switch 2) XX X X X
Line pressure solenoid X X X X X X X
TCC solenoid XX X
Starter relay XX
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A/T CONTROL SYSTEMTM-23
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• This line pressure solenoid controls the pressure regulat or 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.
LINE PRESSURE CONTROL IS BASED ON THE TCM LINE PRESSURE CHARACTERISTIC PAT-
TERN
• 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)
When the select operation is performed during driving and the trans-
mission is shifted down, the line pressure is set according to the
vehicle speed.
During Shift Change
PCIA0007E
PCIA0008E
PCIA0009E
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TM-24
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
The necessary and adequate line pressure for shift change is set.
For this reason, line pressure pattern setting corresponds to input
torque and gearshift selection. Also, line pressure characteristic is
set according 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 ControlINFOID:0000000005148514
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 the engine load state and vehicle driving state. It becomes
possible to finely control the clutch hydraulic pressure with high precision and a smoother shift change charac-
teristic is attained.
SHIFT CHANGE
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
Shift Change System Diagram
PCIA0010E
PCIA0011E
PCIA0012E
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A/T CONTROL SYSTEMTM-25
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*1: Full phase real-time feedback control monitors move ment of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
Lock-up ControlINFOID:0000000005148515
The torque converter clutch piston in the torque conv erter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque conver ter 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.
Lock-up Operation Condition Table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
Lock-up Control System Diagram
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
PCIA0013E
Select lever D position4 position 3 position 2 position
G ear p osit io n 54432
Lock-up ×– ×××
Slip lock-up ××–––
PCIA0014E
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TM-26
< FUNCTION DIAGNOSIS >
A/T CONTROL SYSTEM
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 th is 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 gradually 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 status, the torque converter 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 for 4GR and 5GR at both low speed and when the accelerator has a low
degree of opening.
Engine Brake ControlINFOID:0000000005148516
• The forward one-way clutch transmits the drive force from the engine to the rear wheels. But the reverse drive from the rear wheels is not transmitted to the engine because the one-way clutch is idling.
Therefore, the low coast brake solenoid is operated to prevent the forward one-way clutch from idling and
the engine brake is operated in the same manner as conventionally.
• The operation of the low coast brake solenoid switches the low coast brake switching valve and controls the
coupling and releasing of the low coast brake.
The low coast brake reducing valve contro ls the low coast brake coupling force.
Control ValveINFOID:0000000005148517
FUNCTION OF CONTROL VALVE
SCIA1520E
Name Function
Torque converter regulator valve In order to prevent the pressure supplied to the torque converter from being excessive,
the line pressure is adjusted to the optimum pressure (torque converter operating pres-
sure).
Pressure regu lator valve
Pressure regulator plug
Pressure regu lator sleeve Adjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valve When the front brake is coupled, adjusts the line pressure to the optimum pressure (front
brake pressure) and supplies it to the front brake. (In 1GR, 2GR, 3GR, and 5GR, adjusts
the clutch pressure.)
Accumulator control valve Adjusts the pressure (accumulator control pressure) acting on the accumulator piston
and low coast reducing valve to the pressure appropriate to the driving state.
Revision: April 20092010 QX56

A/T CONTROL SYSTEMTM-27
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FUNCTION OF PRESSURE SWITCH
Pilot valve A Adjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve B Adjusts the line pressure and produces the constant pressure (pilot pressure) required
for shift change control.
Low coast brake switching valve During engine braking, supplies the line pressure to the low coast brake reducing valve.
Low coast brake reducing valve When the low coast brake is coupled, adjusts the line pressure to the optimum pressure
(low coast brake pressure) and supplies it to the low coast brake.
N-R accumulator Produces the stabilizing pressure for when N-R is selected.
Direct clutch piston switching valve Operates in 4GR and switches the direct clutch coupling capacity.
High and low reverse clutch control valve When the high and low reverse clutch is coupled, adjusts the line pressure to the opti-
mum pressure (high and low reverse clutch pressure) and supplies it to the high and low
reverse clutch. (In 1GR, 3GR, 4GR and 5GR, adjusts the clutch pressure.)
Input clutch control valve When the input clutch is coupled, adjusts the line pressure to the optimum pressure (in-
put clutch pressure) and supplies it to the input clutch. (In 4GR and 5GR, adjusts the
clutch pressure.)
Direct clutch control valve When the direct clutch is coupled, adjusts the line pressure to the optimum pressure (di-
rect clutch pressure) and supplies it to the direct clutch. (In 2GR, 3GR, and 4GR, adjusts
the clutch pressure.)
TCC control valve
TCC control plug
TCC control sleeve Switches the lock-up to operating or released. Also, by performing the lock-up operation
transiently, lock-up smoothly.
Torque converter lubrication valve Operates during lock-up to switch the torque converter, cooling, and lubrication system
oil path.
Cool bypass valve Allows excess oil to bypass cooler circuit without being fed into it.
Line pressure relief valve Discharges excess oil from line pressure circuit.
N-D accumulator Produces the stabilizing pressure for when N-D is selected.
Manual valve Sends line pressure to each circuit according to the select position. The circuits to which
the line pressure is not sent drain.
Name
Function
Name Function
Pressure switch 2 (LC/B) Detects any malfunction in the low coast brake hydraulic pressure. When it detects any
malfunction, it puts the system into fail-safe mode.
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (TCM)TM-33
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4GR INCORRECT RA-
TIO • A/T cannot shift to 4GR.
P0734 P0734TM-62
5GR INCORRECT RA-
TIO• A/T cannot shift to 5GR.
P0735 P0735TM-64
TORQUE CONVERT-
ER• Normal voltage not applied to solenoid due to cut line,
short, or the like. P0740 P0740
TM-65
TORQUE CONVERT-
ER• A/T cannot perform lock-up even if electrical circuit is
good.
• TCM detects as irregular by comparing difference val-
ue with slip rotation. P0744 P0744*2
TM-68
PC SOLENOID A• Normal voltage not applied to solenoid due to cut line,
short, or the like.
• TCM detects as irregular by comparing target value
with monitor value. P0745 P0745
TM-69
TP SENSOR• TCM does not receive the proper accelerator pedal po-
sition signals (input by CAN communication) from
ECM. P1705 P1705
TM-71
FLUID TEMP SENSOR• During running, the ATF temperature sensor signal
voltage is excessively high or low. P1710 P0710
TM-73
VEHICLE SPEED SIG-
NAL• Signal (CAN communication) from vehicle speed sig-
nal not input due to cut line or the like.
• Unexpected signal input during running. P1721
—TM-76
INTERLOCK • Except during shift change, the gear position and ATF
pressure switch states are monitored and comparative
judgement made. P1730 P1730
TM-78
1GR E/BRAKING• Each ATF pressure switch and solenoid current is
monitored and if a pattern is detected having engine
braking 1GR other than in the "1" position, a malfunc-
tion is detected. P1731
—TM-80
INPUT CLUTCH SOLE-
NOID • Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like.
• TCM detects as irregular by comparing target value
with monitor value. P1752 P1752
TM-82
FR BRAKE SOLENOID• Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like.
• TCM detects as irregular by comparing target value
with monitor value. P1757 P1757
TM-84
DRCT CLUTCH SOLE-
NOID• Normal voltage not applied to solenoid due to cut line,
short, or the like.
• TCM detects as irregular by comparing target value
with monitor value. P1762 P1762
TM-86
HLR CLUTCH SOLE-
NOID• Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like.
• TCM detects as irregular by comparing target value
with monitor value. P1767 P1767
TM-88
L C BRAKE SOLENOID• Normal voltage not applied to solenoid due to function-
al malfunction, cut line, short, or the like. P1772 P1772
TM-90
Items (CONSULT-III
screen terms) Malfunction is detected when... TCM self-di-
agnosis OBD (DTC)
Reference
“TRANSMIS-
SION” with
CONSULT-III MIL indicator
lamp*1, “EN-
GINE” with
CONSULT-III or
GST
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (TCM)TM-37
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DTC & SRT CONFIRMATION
DTC Work Support Mode
Diagnosis Procedure without CONSULT-IIIINFOID:0000000005148527
OBD-II SELF-DIAGNOSTIC PROCEDURE (WITH GST)
Refer to EC-72, "Generic Scan Tool (GST) Function".
OBD-II SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)
Refer to EC-55, "Malfunction Indicator Lamp (MIL)".
TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)
Description
When the ignition switch is switched “ON”, the A/T CHECK indicator lamp lights up for 2 seconds. As a method
for locating the suspect circuit, when the self-diagnosti cs start signal is input, the memory for the malfunction
location is output and the A/T CHECK indicator lamp flashes to display the corresponding DTC.
Diagnostic Procedure
1.CHECK A/T CHECK INDICATOR LAMP
1. Start the engine with selector lever in “P” pos ition. Warm engine to normal operating temperature.
2. Turn ignition switch ON and OFF at least twice, then leave it in the OFF position.
3. Wait 10 seconds.
4. Turn ignition switch ON. (Do not start engine.)
Frequency (Hz) —— X
The value measured by the pulse probe is dis-
played.
DUTY-HI (high) (%)
—— X
DUTY-LOW (low) (%) —— X
PLS WIDTH-HI (ms) —— X
PLS WIDTH-LOW (ms) —— X
Monitored item (Unit)
Monitor Item Selection
Remarks
ECU IN-
PUT SIG- NALS MAIN SIG-
NALS SELEC-
TION
FROM
MENU
DTC work support item DescriptionCheck item
1ST GR FNCTN P0731 Following items for “1GR function ratio” be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnosis result (OK or NG)
• Input clutch solenoid valve
• Front brake solenoid valve
• Direct clutch solenoid valve
• High and low reverse clutch solenoid valve
• Each clutch
• Hydraulic co ntrol circuit
valve
2ND GR FNCTN P0732
Following items for “2GR function ratio” be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnosis result (OK or NG)
3RD GR FNCTN P0733 Following items for “3GR function ratio” be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnosis result (OK or NG)
4TH GR FNCTN P0734 Following items for “4GR function ratio” be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnosis result (OK or NG)
5TH GR FNCTN P0735 Following items for “5GR function ratio” be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnosis result (OK or NG)
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (TCM)TM-39
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Erase Self-diagnosis
• In order to make it easier to find the cause of
hard-to-duplicate malfunctions, malfunction information is
stored into the control unit as necessary during use by the user. This memory is not erased no matter how
many times the ignition switch is turned ON and OFF.
• However, this information is erased by turning ignition switch OFF after executing self-diagnostics or by erasing the memory using the CONSULT-III.
No. Malfunctioning item No.Malfunctioning item
1 Output speed sensor TM-50
12 Interlock TM-78
2 Direct clutch solenoid TM-8613 1st engine braking TM-80
3 Torque converter TM-65, TM-6714 Starter relay TM-41
4 Line pressure solenoid TM-6915 Accelerator pedal position sensor TM-71
5 Input clutch solenoid TM-8216 Engine speed TM-53
6 Front brake solenoid TM-8417 CAN communication line TM-40
7 Low coast brake solenoid TM-90, TM-9218 1GR incorrect ratio TM-55
8 High and low reverse clutch solenoid TM-8819 2GR incorrect ratio TM-57
9 Transmission range switch TM-4520 3GR incorrect ratio TM-59
10 A/T fluid temperature sensor TM-7321 4GR incorrect ratio TM-61
11 Input speed sensor TM-4822 5GR incorrect ratio TM-63
Revision: April 20092010 QX56