2010 INFINITI QX56 lock

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
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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

A/T SHIFT LOCK SYSTEMTM-29
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A/T SHIFT LOCK SYSTEM
System DescriptionINFOID:0000000005148519
• The selector lever cannot be shifted from “P” (Park) unless the brake pedal is applied and the ignition knob switch is turned to the “ON” position.
• The ignition knob switch cannot be returned to the “OFF” position unless the selector lever is placed in “P”
(Park).
• The shift lock mechanism is controlled by t he ON-OFF operation of the shift lock solenoid.
• The key switch and ignition knob switch lock mechanism is controlled by the ON-OFF operation of the key
lock solenoid.
Component Parts LocationINFOID:0000000005148520
1. Emergency lever 2. Key lock solenoid3. Ignition knob switch
4. Shift lock control unit 5. Shift lock solenoid6. Park position switch
7. Shift lock release 8. Stop lamp switch
AWDIA0706ZZ
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

TM-38
< FUNCTION DIAGNOSIS >
DIAGNOSIS SYSTEM (TCM)
Does A/T CHECK indicator lamp come on for about 2 seconds?
YES >> GO TO 2.
NO >> GO TO TM-121, "
Symptom Table".
2.JUDGMENT PROCEDURE STEP 1
1. Turn ignition switch OFF.
2. Keep pressing shift lock release button.
3. Move selector lever from “P” to “D” position.
4. Release accelerator pedal. (Set the closed throttle position signal “ON”.)
5. Depress brake pedal. (Stop lamp switch signal “ON”.)
6. Turn ignition switch ON. (Do not start engine.)
7. Wait 3 seconds.
8. Move the selector lever from “D” to “3” position.
9. Release brake pedal. (Stop lamp switch signal “OFF”.)
10. Move the selector lever from “3” to “2” position.
11. Depress brake pedal. (Stop lamp switch signal “ON”.)
12. Depress accelerator pedal fully and release it.
>> GO TO 3.
3.CHECK SELF-DIAGNOSIS CODE
Check A/T CHECK indicator lamp.
Refer to "Judgment Self-diagnosis Code".
If the system does not go into self-diagnostics. Refer to TM-45, "
Diagnosis Procedure", TM-96, "Diagnosis
Procedure", TM-97, "Diagnosis Procedure".
>> DIAGNOSIS END
Judgment Self-diagnosis Code
If there is a malfunction, the lamp lights up for the time corresponding to the suspect circuit.
JPDIA0024GB
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (TCM)TM-39
< FUNCTION DIAGNOSIS >
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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

TM-48
< COMPONENT DIAGNOSIS >
P0717 INPUT SPEED SENSOR A
P0717 INPUT SPEED SENSOR A
DescriptionINFOID:0000000005148550
The input speed sensor detects input shaft rpm (revolutions per minute). It is located on the input side of the
automatic transmission. Monitors revolution of sensor 1 and sensor 2 for non-standard conditions.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000005148551
On Board Diagnosis LogicINFOID:0000000005148552
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P0717 INPUT SPEED SENSOR A” with CONSULT-III is detected under the follow-
ing conditions.
- When TCM does not receive the proper voltage signal from the sensor.
- When TCM detects an irregularity only at pos ition of 4GR for input speed sensor 2.
Possible CauseINFOID:0000000005148553
• Harness or connectors
(The sensor circuit is open or shorted.)
• Input speed sensor 1, 2
DTC Confirmation ProcedureINFOID:0000000005148554
CAUTION:
Always drive vehicle at a safe speed.
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 proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
3. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL/S SE-A/T: 40 km/h (25 MPH) or more
ENGINE SPEED: 1,500 rpm or more
ACCELE POSI: 0.5/8 or more
SLCT LVR POSI: “D” position
GEAR (Input speed sensor 1): 4th or 5th position
GEAR (Input speed sensor 2): All position
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving
conditions required for this test.
4. If DTC is detected, go to TM-48, "
Diagnosis Procedure".
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000005148555
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONI TOR” mode for “TRANSMISSION” with CONSULT-III.
3. Vehicle start and read out the value of “INPUT SPEED”.
Item name Condition Display value (rpm)
INPUT SPEED During driving (lock-up ON) Approximately matches the engine speed.
Revision: April 20092010 QX56