low oil pressure INFINITI QX56 2007 Factory Service Manual

ACS-12
< SERVICE INFORMATION >[ICC]
LASER BEAM AIMING ADJUSTMENT
LASER BEAM AIMING ADJUSTMENT
Outline of Laser Beam Aiming Adjustment ProcedureINFOID:0000000003533782
CAUTION:
• The laser beam aiming adjustment cannot be performed without CONSULT-II.
• The laser beam aiming adjustment must be performed every time the ICC sensor is removed,
installed or has been moved as a result of a collision.
1. Prepare the vehicle and the work area.
2. Set up the ICC target board. For details, refer to Technical Service Bulletin.
3. Adjust the sensor following the procedure on CONSULT-II.
4. Check system operation after the adjustment.
PreparationINFOID:0000000003533783
• Place the vehicle on level ground. Shift the transmission into "P" position and release the parking brake.
• Adjust the tire pressure to the specified value.
• See that there is no load in the vehicle. Coolant, engine oil and fuel should be filled to correct level.
• Check that the vehicle suspension has been adjusted to the standard height by the load leveling rear air sus-
pension system. Refer to RSU-10, "
Basic Inspection" .
• Clean the sensor with a soft cloth.
Setting up the ICC Target BoardINFOID:0000000003533784
CAUTION:
Accuracy in setting up the ICC target board is essential for the laser beam aiming adjustment. For
details, refer to Technical Service Bulletin.
ADJUSTING HEIGHT OF THE TARGET
1. Attach a triangle scale as shown.Tool number : KV99110100 (J-45718)
LKIA0632E
WKIA1849E

AT-4
DTC Confirmation Procedure ................................152
Diagnosis Procedure .............................................152
DTC P1845 ATF PRESSURE SWITCH 5 ........154
Description .............................................................154
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
154
On Board Diagnosis Logic .....................................154
Possible Cause ......................................................154
DTC Confirmation Procedure ................................154
Diagnosis Procedure .............................................154
DTC P1846 ATF PRESSURE SWITCH 6 ........156
Description .............................................................156
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
156
On Board Diagnosis Logic .....................................156
Possible Cause ......................................................156
DTC Confirmation Procedure ................................156
Diagnosis Procedure .............................................156
MAIN POWER SUPPLY AND GROUND CIR-
CUIT .................................................................
158
Wiring Diagram - AT - MAIN ..................................158
Diagnosis Procedure .............................................159
CLOSED THROTTLE POSITION AND WIDE
OPEN THROTTLE POSITION CIRCUIT .........
161
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
161
Diagnosis Procedure .............................................161
BRAKE SIGNAL CIRCUIT ..............................162
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
162
Diagnosis Procedure .............................................162
TOW MODE SWITCH ......................................163
Description .............................................................163
Wiring Diagram - AT - TMSW ................................163
Diagnosis Procedure .............................................164
TROUBLE DIAGNOSIS FOR SYMPTOMS .....165
Wiring Diagram - AT - NONDTC ............................165
A/T Check Indicator Lamp Does Not Come On .....167
Engine Cannot Be Started in "P" or "N" Position ...168
In "P" Position, Vehicle Moves When Pushed .......168
In "N" Position, Vehicle Moves ..............................169
Large Shock ("N" to "D" Position) ..........................170
Vehicle Does Not Creep Backward in "R" Position ..172
Vehicle Does Not Creep Forward in "D" Position ..175
Vehicle Cannot Be Started from D1 .......................177
A/T Does Not Shift: D1→ D2 ..................................179
A/T Does Not Shift: D2→ D3 ..................................181
A/T Does Not Shift: D3→ D4 ..................................183
A/T Does Not Shift: D4→ D5 ..................................185
A/T Does Not Perform Lock-up .............................187
A/T Does Not Hold Lock-up Condition ...................189
Lock-up Is Not Released .......................................190
Engine Speed Does Not Return to Idle .................191
A/T Does Not Shift: 5th gear → 4th gear ..............192
A/T Does Not Shift: 4th gear → 3rd gear ..............194
A/T Does Not Shift: 3rd gear → 2nd gear .............196
A/T Does Not Shift: 2nd gear → 1st gear .............197
Vehicle Does Not Decelerate By Engine Brake ....199
A/T SHIFT LOCK SYSTEM ..............................202
Description ............................................................202
Shift Lock System Electrical Parts Location ..........202
Wiring Diagram - AT - SHIFT ................................203
Shift Lock Control Unit Reference Value ..............204
Component Inspection ..........................................204
SHIFT CONTROL SYSTEM .............................207
Control Device Removal and Installation ..............207
Adjustment of A/T Position ....................................208
Checking of A/T Position .......................................208
ON-VEHICLE SERVICE ...................................209
Oil Pan ..................................................................209
Control Valve with TCM and A/T Fluid Tempera-
ture Sensor 2 ........................................................
210
Rear Oil Seal .........................................................219
AIR BREATHER HOSE ....................................221
Removal and Installation .......................................221
TRANSMISSION ASSEMBLY ..........................223
Removal and Installation (2WD) ...........................223
Removal and Installation (4WD) ...........................225
OVERHAUL ......................................................228
Component ...........................................................228
Oil Channel ...........................................................235
Location of Adjusting Shims, Needle Bearings,
Thrust Washers and Snap Rings ..........................
237
DISASSEMBLY ................................................240
Disassembly ..........................................................240
REPAIR FOR COMPONENT PARTS ..............258
Oil Pump ...............................................................258
Front Sun Gear, 3rd One-Way Clutch ...................260
Front Carrier, Input Clutch, Rear Internal Gear .....262
Mid Sun Gear, Rear Sun Gear, High and Low Re-
verse Clutch Hub ..................................................
267
High and Low Reverse Clutch ..............................272
Direct Clutch .........................................................274
ASSEMBLY ......................................................277
Assembly (1) .........................................................277
Adjustment ............................................................290
Assembly (2) .........................................................292
SERVICE DATA AND SPECIFICATIONS
(SDS) ................................................................
298
General Specification ............................................298
Vehicle Speed When Shifting Gears .....................298
Vehicle Speed When Performing and Releasing
Complete Lock-up .................................................
299
Stall Speed ............................................................299

A/T CONTROL SYSTEM
AT-35
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
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:0000000003532234
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

A/T CONTROL SYSTEM
AT-37
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
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 converter 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 torque fluctuation and lock-up operates from low speed.
This raises the fuel efficiency for 4th and 5th gears at both low speed and when the accelerator has a low
degree of opening.
Engine Brake ControlINFOID:0000000003532236
• 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 controls the low coast brake coupling force.
Control ValveINFOID:0000000003532237
FUNCTION OF CONTROL VALVE
SCIA1520E
Name Function
Torque converter regulator valveIn 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 regulator valve
Pressure regulator plug
Pressure regulator sleeveAdjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valveWhen the front brake is coupled, adjusts the line pressure to the optimum pressure (front
brake pressure) and supplies it to the front brake. (In 1st, 2nd, 3rd, and 5th gears, adjusts
the clutch pressure.)
Accumulator control valveAdjusts the pressure (accumulator control pressure) acting on the accumulator piston
and low coast reducing valve to the pressure appropriate to the driving state.

AT-38
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
FUNCTION OF PRESSURE SWITCH
Pilot valve AAdjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve BAdjusts 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 valveWhen 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 4th gear and switches the direct clutch coupling capacity.
High and low reverse clutch control valveWhen 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 1st, 3rd, 4th and 5th gears, adjusts the clutch pressure.)
Input clutch control valveWhen 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 4th and 5th gears, adjusts the
clutch pressure.)
Direct clutch control valveWhen 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 2nd, 3rd, and 4th gears, ad-
justs the clutch pressure.)
TCC control valve
TCC control plug
TCC control sleeveSwitches the lock-up to operating or released. Also, by performing the lock-up operation
transiently, lock-up smoothly.
Torque converter lubrication valveOperates 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 valveSends 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 1 (FR/B)Detects any malfunction in the front brake hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
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.
Pressure switch 3 (I/C)Detects any malfunction in the input clutch hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
Pressure switch 5 (D/C)Detects any malfunction in the direct clutch hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
Pressure switch 6 (HLR/C)Detects any malfunction in the high and low reverse clutch hydraulic pressure. When it
detects any malfunction, it puts the system into fail-safe mode.

TROUBLE DIAGNOSIS
AT-53
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P Judgement of Stall Test
O: Stall speed within standard value position
H: Stall speed higher than standard value
L: Stall speed lower than standard value
Stall test standard value position
LINE PRESSURE TEST
Line Pressure Test Port
Line Pressure Test Procedure
1. Inspect the amount of engine oil and replenish if necessary.
2. Drive the car for about 10 minutes to warm it up so that the ATF reaches in range of 50 to 80°C (122 to
176°F), then inspect the amount of ATF and replenish if necessary.
NOTE:
The automatic fluid temperature rises in range of 50 to 80°C (122 to 176°F) during 10 minutes of
driving.
3. After warming up remove the oil pressure detection plug and
install the oil pressure gauge [ST2505S001(J-34301-C)].
CAUTION:
When using the oil pressure gauge, be sure to use the O-
ring attached to the oil pressure detection plug.
Selector lever position
Expected problem location
DR
Stall rotation HO• Forward brake
• Forward one-way clutch
• 1st one-way clutch
• 3rd one-way clutch
O H • Reverse brake
L L • Engine and torque converter one-way clutch
H H • Line pressure low
Does not shift-up D position 1 → 2 Slipping in 2nd, 3rd, 4th gears Direct clutch slippage
Does not shift-up D position 2 → 3 Slipping in 3rd, 4th, 5th gears High and low reverse clutch slippage
Does not shift-up D position 3 → 4 Slipping in 4th, 5th gears Input clutch slippage
Does not shift-up D position 4 → 5 Slipping in 5th gear Front brake slippage
SCIA2187E
SCIA5309E

AT-54
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
4. Securely engage the parking brake so that the tires do not turn.
5. Start the engine, then measure the line pressure at both idle and
the stall speed.
CAUTION:
• Keep the brake pedal pressed all the way down during
measurement.
• When measuring the line pressure at the stall speed, refer
to "STALL TEST ".
6. After the measurements are complete, install the oil pressure
detection plug and tighten to the regulation torque below.
CAUTION:
Do not reuse the O-ring.
Line Pressure
Judgement of Line Pressure Test
SCIA1224E
:7.3 N·m (0.74 kg-m, 65 in-lb)SAT493G
Engine speedLine pressure [kPa (kg/cm
2, psi)]
R position D position
At idle speed 425 - 465 (4.3 - 4.7, 62 - 67) 379 - 428 (3.9 - 4.4, 55 - 62)
At stall speed 1,605 - 1,950 (16.4 - 19.9, 233 - 283) 1,310 - 1,500 (13.4 - 15.3, 190 - 218)
Judgement Possible cause
Idle speedLow for all positions
(P, R, N, D)Possible causes include malfunctions in the pressure supply system and low oil pump output.
For example
•Oil pump wear
• Pressure regulator valve or plug sticking or spring fatigue
• Oil strainer ⇒ oil pump ⇒ pressure regulator valve passage oil leak
• Engine idle speed too low
Only low for a spe-
cific positionPossible causes include an oil pressure leak in a passage or device related to the position after
the pressure is distributed by the manual valve.
HighPossible causes include a sensor malfunction or malfunction in the line pressure adjustment func-
tion.
For example
• Accelerator pedal position signal malfunction
• ATF temperature sensor malfunction
• Line pressure solenoid malfunction (sticking in “OFF” state, filter clog, cut line)
• Pressure regulator valve or plug sticking

TROUBLE DIAGNOSIS
AT-55
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
ROAD TEST
Description
• The road test inspects overall performance of the A/T and analyzes possible malfunction causes.
• The road test is carried out in the following three stages.
1. Check before engine is started. Refer to AT- 5 5
.
2. Check at idle. Refer to AT- 5 5
3. Cruise test
• Inspect all the items from Part 1 to Part 3. Refer to AT- 5 6
, AT- 5 8, AT- 5 9.
• Before beginning the road test, check the test procedure and inspection items.
• Test all inspection items until the symptom is uncovered. Diagnose NG items when all road tests are com-
plete.
Check Before Engine Is StartedINFOID:0000000003532249
1.CHECK AT CHECK INDICATOR LAMP
1. Park vehicle on level surface.
2. Move selector lever to “P” position.
3. Turn ignition switch to “OFF” position and wait at least 10 seconds.
4. Turn ignition switch to “ON” position. (Do not start engine.)
Does AT CHECK indicator lamp light up for about 2 seconds?
YES >> 1. Turn ignition switch to “OFF” position.
2. Carry out the self-diagnostics and record all NG items on the diagnostics worksheet. Refer to
AT-83, "
CONSULT-II Function (A/T)".
3. Go to AT-55, "
Check at Idle".
NO >> Stop the road test and go to AT-167, "
A/T Check Indicator Lamp Does Not Come On".
Check at IdleINFOID:0000000003532250
1.CHECK STARTING THE ENGINE
1. Park vehicle on level surface.
2. Move selector lever to “P” or “N” position.
3. Turn ignition switch to “OFF” position.
4. Turn ignition switch to “START” position.
Does the engine start?
YES >> GO TO 2.
NO >> Stop the road test and go to AT-168, "
Engine Cannot Be Started in "P" or "N" Position".
2.CHECK STARTING THE ENGINE
1. Turn ignition switch to “ON” position.
2. Move selector lever in “D”,“4”, “3”, “2”, “1” or “R” position.
Stall speedOil pressure does
not rise higher than
the oil pressure for
idle.Possible causes include a sensor malfunction or malfunction in the pressure adjustment function.
For example
• Accelerator pedal position signal malfunction
• TCM breakdown
• Line pressure solenoid malfunction (shorting, sticking in“ ON” state)
• Pressure regulator valve or plug sticking
• Pilot valve sticking or pilot filter clogged
The pressure rises,
but does not enter
the standard posi-
tion.Possible causes include malfunctions in the pressure supply system and malfunction in the pres-
sure adjustment function.
For example
• Accelerator pedal position signal malfunction
• Line pressure solenoid malfunction (sticking, filter clog)
• Pressure regulator valve or plug sticking
• Pilot valve sticking or pilot filter clogged
Only low for a spe-
cific positionPossible causes include an oil pressure leak in a passage or device related to the position after
the pressure is distributed by the manual valve. Judgement Possible cause

AT-68
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
22
Slips/Will
Not En-
gageWhen “D” position, re-
mains in 5th gear.ON vehicle1. Fluid level and stateAT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT- 1 2 4

3. ATF pressure switch 1 and front brake solenoid valveAT- 1 5 0
,
AT- 1 3 4
4. Line pressure testAT- 5 1
5. CAN communication lineAT- 9 1
6. Control valve with TCMAT- 2 1 0
OFF vehicle7. Front brake (brake band)AT- 2 4 08. Input clutchAT- 2 6 2
9. Gear systemAT- 2 2 8
10. High and low reverse clutchAT- 2 7 2
23Vehicle cannot be
started from D
1.
Refer to AT-177, "
Ve -
hicle Cannot Be Start-
ed from D1".ON vehicle1. Fluid level and stateAT- 5 1
2. Accelerator pedal position sensorAT- 11 7
3. Line pressure testAT- 5 1
4. CAN communication lineAT- 9 1
5. Control valve with TCMAT- 2 1 0
OFF vehicle6. Torque converterAT- 2 4 0
7. Oil pump assemblyAT- 2 5 8
8. 3rd one-way clutchAT- 2 6 0
9. 1st one-way clutchAT- 2 6 7
10. Gear systemAT- 2 2 8
11. Reverse brakeAT- 2 4 0
12. Forward one-way clutch (Parts behind drum support is im-
possible to perform inspection by disassembly. Refer to AT-
19, AT- 2 0.)AT- 2 4 0
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 9
, AT- 2 0.)AT- 2 4 0
24Does not lock-up.
Refer to AT-187, "A/T
Does Not Perform
Lock-up".ON vehicle1. Fluid level and stateAT- 5 1
2. Line pressure testAT- 5 1
3. Engine speed signalAT- 1 0 9
4. Turbine revolution sensorAT- 1 0 3
5. Torque converter clutch solenoid valveAT- 111
6. CAN communication lineAT- 9 1
7. Control valve with TCMAT- 2 1 0
OFF vehicle8. Torque converterAT- 2 4 09. Oil pump assemblyAT- 2 5 8
No. Items Symptom Condition Diagnostic ItemReference
page

AT-70
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
28
Slips/Will
Not en-
gageNo shock at all or the
clutch slips when vehi-
cle changes speed D2
→ D
3.ON vehicle1. Fluid level and stateAT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT- 1 2 4
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 5 6,
AT- 1 4 2
4. CAN communication lineAT- 9 1
5. Line pressure testAT- 5 1
6. Control valve with TCMAT- 2 1 0
OFF vehicle7. Torque converterAT- 2 4 0
8. Oil pump assemblyAT- 2 5 8
9. 3rd one-way clutchAT- 2 6 0
10. Gear systemAT- 2 2 8
11. High and low reverse clutchAT- 2 7 2
12. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to AT-
19, AT- 2 0.)AT- 2 4 0
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 9
, AT- 2 0.)AT- 2 4 0
29No shock at all or the
clutch slips when vehi-
cle changes speed D3
→ D
4.ON vehicle1. Fluid level and stateAT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT- 1 2 4
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 5 2,
AT- 1 3 0

4. ATF pressure switch 1 and front brake solenoid valveAT- 1 5 0
,
AT- 1 3 4
5. CAN communication lineAT- 9 1
6. Line pressure testAT- 5 1
7. Control valve with TCMAT- 2 1 0
OFF vehicle8. Torque converterAT- 2 4 0
9. Oil pump assemblyAT- 2 5 8
10. Input clutchAT- 2 6 2
11. Gear systemAT- 2 2 8
12. High and low reverse clutchAT- 2 7 2
13. Direct clutchAT- 2 7 4
No. Items Symptom Condition Diagnostic ItemReference
page