Oil INFINITI QX56 2010 Factory Service Manual

A/T CONTROL SYSTEMTM-25
< FUNCTION DIAGNOSIS >
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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
Revision: April 20092010 QX56

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
< FUNCTION DIAGNOSIS >
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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

P0745 PRESSURE CONTROL SOLENOID ATM-69
< COMPONENT DIAGNOSIS >
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P0745 PRESSURE CONTROL SOLENOID A
DescriptionINFOID:0000000005148605
The line pressure solenoid valve regulates the oil pum p discharge pressure to suit the driving condition in
response to a signal sent from the TCM.
The line pressure duty cycle value is not consistent when the closed throttle position signal is “ON”.
To confirm the line pressure duty cycle at low pressu re, the accelerator (throttle) should be open until
the closed throttle posi tion signal is “OFF”.
CONSULT-III Reference Val ue in Data Monitor ModeINFOID:0000000005148606
On Board Diagnosis LogicINFOID:0000000005148607
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P0745 PC SOLENOID A” with CONSULT-III is detected under the following condi-
tions.
- When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
- When TCM detects as irregular by comparing target value with monitor value.
Possible CauseINFOID:0000000005148608
• Harness or connectors (The solenoid circuit is open or shorted.)
• Line pressure solenoid valve
DTC Confirmation ProcedureINFOID:0000000005148609
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON” and select “DATA MONITOR” mode for “ENGINE” with CONSULT-III.
2. Engine start and wait at least 5 second.
3. If DTC is detected, go to TM-69, "
Diagnosis Procedure".
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000005148610
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start the engine.
4. Read out the value of “LINE PRES SOL” while driving.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
Item name Condition Display value (Approx.)
LINE PRES SOL During driving 0.2 - 0.6 A
Item nameCondition Display value (Approx.)
LINE PRES SOL During driving 0.2 - 0.6 A
Revision: April 20092010 QX56

TM-128
< SYMPTOM DIAGNOSIS >
SYSTEM SYMPTOM
22Slips/Will
Not En-
gage When “D” position, re-
mains in 5GR.
ON vehicle1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Front brake solenoid valve TM-84
4. Line pressure testTM-157
5. CAN communication line LAN-4
6. Control valve with TCMTM-172
OFF vehicle7. Front brake (brake band)
TM-1728. Input clutchTM-172
9. Gear systemTM-172
10. High and low reverse clutchTM-172
23Vehicle cannot be
started from D1.ON vehicle
1. Fluid level and state
TM-148
2. Accelerator pedal position sensor TM-71
3. Line pressure testTM-157
4. CAN communication line LAN-4
5. Control valve with TCMTM-172
OFF vehicle6. Torque converter
TM-172
7. Oil pump assemblyTM-223
8. 3rd one-way clutchTM-172
9. 1st one-way clutchTM-232
10. Gear systemTM-172
11. Reverse brakeTM-172
12. Forward one-way clutch (Parts behind drum support is im-
possible to perform inspection by disassembly. Refer to TM-
8, TM-9. TM-172
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
24
Does not lock-up. ON vehicle1. Fluid level and state
TM-148
2. Line pressure testTM-157
3. Engine speed signal TM-53
4. Input speed sensorTM-48
5. Torque converter clutch solenoid valveTM-65
6. CAN communication line LAN-4
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-1729. Oil pump assemblyTM-172
No. ItemsSymptom Condition Diagnostic ItemReference
page
Revision: April 20092010 QX56

SYSTEM SYMPTOMTM-129
< SYMPTOM DIAGNOSIS >
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25
Slips/Will
Not en-
gage Does not hold lock-up
condition.
ON vehicle1. Fluid level and state
TM-148
2. Line pressure testTM-157
3. Engine speed signal TM-53
4. Input speed sensorTM-48
5. Torque converter clutch solenoid valveTM-65
6. CAN communication line LAN-4
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-1729. Oil pump assemblyTM-172
26Lock-up is not re-
leased. ON vehicle1. Fluid level and state
TM-148
2. Line pressure testTM-157
3. Engine speed signal TM-53
4. Input speed sensorTM-48
5. Torque converter clutch solenoid valveTM-65
6. CAN communication line LAN-4
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-1729. Oil pump assemblyTM-172
27No shock at all or the
clutch slips when vehi-
cle changes speed D1
→
D2. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Direct clutch solenoid valve TM-86
4. CAN communication line LAN-4
5. Line pressure testTM-157
6. Control valve with TCMTM-172
OFF vehicle7. Torque converter
TM-172
8. Oil pump assemblyTM-172
9. 3rd one-way clutchTM-172
10. Gear systemTM-172
11. Direct clutchTM-172
12. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to TM-8
, TM-9. TM-172
No. Items
Symptom Condition Diagnostic ItemReference
page
Revision: April 20092010 QX56

TM-130
< SYMPTOM DIAGNOSIS >
SYSTEM SYMPTOM
28Slips/Will
Not en-
gage No shock at all or the
clutch slips when vehi-
cle changes speed D2
→ D3.
ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. High and low reverse clutch solenoid valve TM-88
4. CAN communication line LAN-4
5. Line pressure testTM-157
6. Control valve with TCMTM-172
OFF vehicle7. Torque converter
TM-172
8. Oil pump assemblyTM-172
9. 3rd one-way clutchTM-172
10. Gear systemTM-172
11. High and low reverse clutchTM-172
12. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
29 No shock at all or the
clutch slips when vehi-
cle changes speed D3
→ D4. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Input clutch solenoid valve TM-82
4. Front brake solenoid valveTM-84
5. CAN communication line LAN-4
6. Line pressure testTM-157
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-172
9. Oil pump assemblyTM-172
10. Input clutchTM-172
11. Gear systemTM-172
12. High and low reverse clutchTM-172
13. Direct clutchTM-172
No. ItemsSymptom Condition Diagnostic ItemReference
page
Revision: April 20092010 QX56

SYSTEM SYMPTOMTM-131
< SYMPTOM DIAGNOSIS >
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Slips/Will
Not en-
gage No shock at all or the
clutch slips when vehi-
cle changes speed D4
→
D5. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Front brake solenoid valve TM-84
4. Direct clutch solenoid valveTM-86
5. CAN communication line LAN-4
6. Line pressure testTM-157
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-172
9. Oil pump assemblyTM-172
10. Front brake (brake band)TM-172
11. Input clutchTM-172
12. Gear systemTM-172
13. High and low reverse clutchTM-172
31When you press the
accelerator pedal and
shift speed D5→ D4
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Front brake solenoid valve TM-84
4. Direct clutch solenoid valveTM-86
5. CAN communication line LAN-4
6. Line pressure testTM-157
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-172
9. Oil pump assemblyTM-172
10. Input clutchTM-172
11. Gear systemTM-172
12. High and low reverse clutchTM-172
13. Direct clutchTM-172
No. ItemsSymptom Condition Diagnostic ItemReference
page
Revision: April 20092010 QX56

TM-132
< SYMPTOM DIAGNOSIS >
SYSTEM SYMPTOM
32Slips/Will
Not en-
gage When you press the
accelerator pedal and
shift speed D4→ D3
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Input clutch solenoid valve TM-82
4. Front brake solenoid valveTM-84
5. CAN communication line LAN-4
6. Line pressure testTM-157
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-172
9. Oil pump assemblyTM-172
10. 3rd one-way clutchTM-172
11. Gear systemTM-172
12. High and low reverse clutchTM-172
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
33 When you press the
accelerator pedal and
shift speed D3→ D2
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. High and low reverse clutch solenoid valve TM-88
4. Direct clutch solenoid valveTM-86
5. CAN communication line LAN-4
6. Line pressure testTM-157
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-172
9. Oil pump assemblyTM-172
10. 3rd one-way clutchTM-172
11. Gear systemTM-172
12. Direct clutchTM-172
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to TM-8
, TM-9. TM-172
No. Items
Symptom Condition Diagnostic ItemReference
page
Revision: April 20092010 QX56

SYSTEM SYMPTOMTM-133
< SYMPTOM DIAGNOSIS >
CEF
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34
Slips/Will
Not En-
gage When you press the
accelerator pedal and
shift speed D2→ D1
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
TM-148
2. Output speed sensor and vehicle speed signal TM-50,
TM-76
3. Direct clutch solenoid valve TM-86
4. CAN communication line LAN-4
5. Line pressure testTM-157
6. Control valve with TCMTM-172
OFF vehicle7. Torque converter
TM-172
8. Oil pump assemblyTM-172
9. 3rd one-way clutchTM-172
10. 1st one-way clutchTM-172
11. Gear systemTM-172
12. Reverse brakeTM-172
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
TM-8
, TM-9.TM-172
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
35 With selector lever in
“D” position, accelera-
tion is extremely poor. ON vehicle
1. Fluid level and state
TM-148
2. Line pressure testTM-157
3. Accelerator pedal position sensor TM-71
4. CAN communication line LAN-4
5. Transmission range switchTM-45
6. Control cable adjustmentTM-164
7. Control valve with TCMTM-172
OFF vehicle8. Torque converter
TM-204
9. Oil pump assemblyTM-172
10. 1st one-way clutchTM-172
11. Gear systemTM-172
12. Reverse brakeTM-172
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
TM-8
, TM-9.TM-172
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
TM-8
, TM-9. TM-172
No. Items
Symptom Condition Diagnostic ItemReference
page
Revision: April 20092010 QX56