2007 INFINITI QX56 brake fluid

A/T CONTROL SYSTEM
AT-33
< SERVICE INFORMATION >
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Input/Output Signal of TCMINFOID:0000000003532232
*1: Spare for vehicle speed sensor·A/T (revolution 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 communications
Line Pressure ControlINFOID:0000000003532233
• 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 itemLine
pressure
controlVehicle
speed
controlShift
controlLock-up
controlEngine
brake
controlFail-safe
function
(*3)Self-diag-
nostics
function
InputAccelerator pedal position signal
(*4)XXXXXXX
Vehicle speed sensor A/T
(revolution sensor)XXXX XX
Vehicle speed sensor MTR
(*1) (*4)XXXX X
Closed throttle position signal
(*4)(*2) X (*2) X X (*2) X X
Wide open throttle position signal
(*4)(*2) X (*2) X (*2) X X
Turbine revolution sensor 1 X X X X X
Turbine revolution sensor 2
(for 4th speed only)XXXXX
Engine speed signals
(*4)XX
PNP switch XXXXXXX
A/T fluid temperature sensors 1, 2 X X X X X X X
ASCDOperation signal
(*4)XXXX
Overdrive cancel sig-
nal
(*4)XXX
TCM power supply voltage signal X X X X X X
Out-
putDirect clutch solenoid (ATF pressure
switch 5)XX XX
Input clutch solenoid (ATF pressure
switch 3)XX XX
High and low reverse clutch sole-
noid (ATF pressure switch 6)XX XX
Front brake solenoid (ATF pressure
switch 1)XX XX
Low coast brake solenoid (ATF
pressure switch 2)XX XXX
Line pressure solenoid X X X X X X X
TCC solenoid X X X
Starter relayXX

A/T CONTROL SYSTEM
AT-35
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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

AT-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Fluid Condition Check
Inspect the fluid condition.
STALL TEST
Stall Test Procedure
1. Inspect the amount of engine oil. Replenish the engine oil if necessary.
2. Drive for about 10 minutes to warm up the vehicle so that the A/
T fluid temperature is 50 to 80°C (122 to 176°F). Inspect the
amount of ATF. Replenish if necessary.
3. Securely engage the parking brake so that the tires do not turn.
4. Engine start, apply foot brake, and place selector lever in “D”
position.
5. While holding down the foot brake, gradually press down the
accelerator pedal.
6. Quickly read off the stall speed, then quickly remove your foot
from the accelerator pedal.
CAUTION:
Do not hold down the accelerator pedal for more than 5 sec-
onds during this test.
7. Move the selector lever to the “N” position.
8. Cool down the ATF.
CAUTION:
Run the engine at idle for at least one minute.
Fluid condition Conceivable Cause Required Operation
Varnished (viscous
varnish state)Clutch, brake
scorchedReplace the ATF and check the A/T
main unit and the vehicle for mal-
functions (wire harnesses, cooler
pipes, etc.)
Milky white or
cloudyWater in the fluidReplace the ATF and check for plac-
es where water is getting in.
Large amount of
metal powder mixed
inUnusual wear of
sliding parts within
A/TReplace the ATF and check for im-
proper operation of the A/T.
SAT638A
SAT647B
SCIA1224E
Stall speed: 2,500 - 2,800 rpm
SAT514G

TROUBLE DIAGNOSIS
AT-53
< SERVICE INFORMATION >
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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

TROUBLE DIAGNOSIS
AT-61
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No. Items Symptom Condition Diagnostic ItemReference
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1
Shift
ShockLarge shock. (“N” →“
D” position)
Refer to AT- 1 7 0 ,
"Large Shock ("N" to
"D" Position)".ON vehicle1. Engine idle speedEC-75
2. Engine speed signalAT-109
3. Accelerator pedal position sensorAT- 11 7
4. Control cable adjustmentAT-208
5. ATF temperature sensorAT- 11 9
6. ATF pressure switch 1 and front brake solenoid valveAT- 1 5 0,
AT-134
7. CAN communication lineAT- 9 1
8. Fluid level and stateAT- 5 1
9. Line pressure testAT- 5 1
10. Control valve with TCMAT-210
OFF vehicle11. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 9, AT- 2 0.)AT-240
2Shock is too large
when changing D1 →
D
2.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT-208
3. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 5 4,
AT-138
4. CAN communication lineAT- 9 1
5. Engine speed signalAT-109
6. Turbine revolution sensorAT-103
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT-124
8. Fluid level and stateAT- 5 1
9. Control valve with TCMAT-210
OFF vehicle 10. Direct clutchAT-274
3Shock is too large
when changing D2 →
D
3.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT-208
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 5 6,
AT-142
4. CAN communication lineAT- 9 1
5. Engine speed signalAT-109
6. Turbine revolution sensorAT-103
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT-124
8. Fluid level and stateAT- 5 1
9. Control valve with TCMAT-210
OFF vehicle 10. High and low reverse clutchAT-272

AT-62
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
4
Shift
ShockShock is too large
when changing D3 →
D
4.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT- 2 0 8
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 5 2,
AT- 1 3 0
4. CAN communication lineAT- 9 1
5. Engine speed signalAT- 1 0 9
6. Turbine revolution sensorAT- 1 0 3
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT- 1 2 4
8. Fluid level and stateAT- 5 1
9. Control valve with TCMAT- 2 1 0
OFF vehicle 10. Input clutchAT- 2 6 2
5Shock is too large
when changing D4 →
D
5.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT- 2 0 8
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 5 0,
AT- 1 3 4

4. CAN communication lineAT- 9 1
5. Engine speed signalAT- 1 0 9
6. Turbine revolution sensorAT- 1 0 3
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT- 1 2 4
8. Fluid level and stateAT- 5 1
9. Control valve with TCMAT- 2 1 0
OFF vehicle10. Front brake (brake band)AT- 2 2 811. Input clutchAT- 2 6 2
6Shock is too large for
downshift when accel-
erator pedal is
pressed.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT- 2 0 8
3. CAN communication lineAT- 9 1
4. Engine speed signalAT- 1 0 9
5. Turbine revolution sensorAT- 1 0 3
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT- 1 2 4
7. Fluid level and stateAT- 5 1
8. Control valve with TCMAT- 2 1 0
OFF vehicle9. Front brake (brake band)AT- 2 2 8
10. Input clutchAT- 2 6 2
11. High and low reverse clutchAT- 2 7 2AT-
272
12. Direct clutchAT- 2 7 4
No. Items Symptom Condition Diagnostic ItemReference
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TROUBLE DIAGNOSIS
AT-63
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Shift
ShockShock is too large for
upshift when accelera-
tor pedal is released.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT-208
3. Engine speed signalAT-109
4. CAN communication lineAT- 9 1
5. Turbine revolution sensorAT-103
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT-124
7. Fluid level and stateAT- 5 1
8. Control valve with TCMAT-210
OFF vehicle9. Front brake (brake band)AT-22810. Input clutchAT-262
11. High and low reverse clutchAT-272
12. Direct clutchAT-274
8Shock is too large for
lock-up.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT-208
3. Engine speed signalAT-109
4. CAN communication lineAT- 9 1
5. Turbine revolution sensorAT-103
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 5,
AT-124
7. Torque converter clutch solenoid valveAT- 111
8. Fluid level and stateAT- 5 1
9. Control valve with TCMAT-210
OFF vehicle 10. Torque converterAT-240
9Shock is too large dur-
ing engine brake.ON vehicle1. Accelerator pedal position sensorAT- 11 7
2. Control cable adjustmentAT-208
3. CAN communication lineAT- 9 1
4. Fluid level and stateAT- 5 1
5. Control valve with TCMAT-210
OFF vehicle6. Front brake (brake band)AT-2287. Input clutchAT-262
8. High and low reverse clutchAT-272
9. Direct clutchAT-274
No. Items Symptom Condition Diagnostic ItemReference
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AT-64
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
10
No Up
ShiftGear does not change
from D → D
2.
Refer to AT-179, "
A/T
Does Not Shift: D1→
D2".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 5 and direct clutch solenoid valveAT- 1 5 4,
AT- 1 3 8
4. Line pressure testAT- 5 1
5. CAN communication lineAT- 9 1
6. Control valve with TCMAT- 2 1 0
OFF vehicle 7. Direct clutchAT- 2 7 4
11Gear does not change
from D → D3.
Refer to AT-181, "
A/T
Does Not Shift: D2→
D3".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. Line pressure testAT- 5 1
5. CAN communication lineAT- 9 1
6. Control valve with TCMAT- 2 1 0
OFF vehicle 7. High and low reverse clutchAT- 2 7 2
12Gear does not change
from D → D
4.
Refer to AT-183, "
A/T
Does Not Shift: D3→
D4".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. Line pressure testAT- 5 1
6. CAN communication lineAT- 9 1
7. Control valve with TCMAT- 2 1 0
OFF vehicle 8. Input clutchAT- 2 6 2
13Gear does not change
from D → D
5.
Refer to AT-185, "
A/T
Does Not Shift: D4→
D5".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. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 5 4,
AT- 1 3 8
5. Turbine revolution sensorAT- 1 0 3
6. Line pressure testAT- 5 1
7. CAN communication lineAT- 9 1
8. Control valve with TCMAT- 2 1 0
OFF vehicle9. Front brake (brake band)AT- 2 4 010. Input clutchAT- 2 6 2
No. Items Symptom Condition Diagnostic ItemReference
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