2007 INFINITI QX56 Parking brake

A/T CONTROL SYSTEM
AT-31
< SERVICE INFORMATION >
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TCM FunctionINFOID:0000000003532230
The function of the TCM is to:
• Receive input signals sent from various switches and sensors.
• Determine required line pressure, shifting point, lock-up operation, and engine brake operation.
• Send required output signals to the respective solenoids.
CONTROL SYSTEM OUTLINE
The automatic transmission senses vehicle operating conditions through various sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
1. Front brake 2. Input clutch 3. Direct clutch
4. High and low reverse clutch 5. Reverse brake 6. Forward brake
7. Low coast brake 8. 1st one-way clutch 9. Forward one-way clutch
10. 3rd one-way clutch 11. Front sun gear 12. Input shaft
13. Mid internal gear 14. Front internal gear 15. Rear carrier
16. Rear sun gear 17. Mid sun gear 18. Front carrier
19. Mid carrier 20. Rear internal gear 21. Output shaft
22. Parking gear 23. Parking pawl
SCIA1519E

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

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

AT-56
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
3. Turn ignition switch to “START” position.
Does the engine start in either position?
YES >> Stop the road test and go to AT-168, "Engine Cannot Be Started in "P" or "N" Position".
NO >> GO TO 3.
3.CHECK “P” POSITION FUNCTIONS
1. Move selector lever to “P” position.
2. Turn ignition switch to “OFF” position.
3. Release the parking brake.
4. Push the vehicle forward or backward.
5. Engage the parking brake.
When you push the vehicle with disengaging the parking brake, does it move?
YES >> Enter a check mark at “In “P” Position Vehicle Moves When Pushed” on the diagnostics work-
sheet, then continue the road test.
NO >> GO TO 4.
4.CHECK “N” POSITION FUNCTIONS
1. Start the engine.
2. Move selector lever to “N” position.
3. Release the parking brake.
Does vehicle move forward or backward?
YES >> Enter a check mark at “In “N” Position Vehicle Moves” on the diagnostics worksheet, then con-
tinue the road test.
NO >> GO TO 5.
5.CHECK SHIFT SHOCK
1. Engage the brake.
2. Move selector lever to “D” position.
When the transmission is shifted from
“N” to “D”, is there an excessive shock?
YES >> Enter a check mark at “Large Shock ("N" to "D" Position) on the diagnostics worksheet, then con-
tinue the road test.
NO >> GO TO 6.
6.CHECK “R” POSITION FUNCTIONS
1. Engage the brake.
2. Move selector lever to “R” position.
3. Release the brake for 4 to 5 seconds.
Does the vehicle creep backward?
YES >> GO TO 7.
NO >> Enter a check mark at “Vehicle Does Not Creep Backward In "R" Position” on the diagnostics
worksheet, then continue the road test.
7.CHECK “D” POSITION FUNCTIONS
Inspect whether the vehicle creeps forward when the transmission is put into the “D” position.
Does the vehicle creep forward in the
“D” positions?
YES >> Go to AT-56, "Cruise Test - Part 1", AT-58, "Cruise Test - Part 2", and AT-59, "Cruise Test - Part 3".
NO >> Enter a check mark at “Vehicle Does Not Creep Forward in "D" Position” on the diagnostics work-
sheet, then continue the road test.
Cruise Test - Part 1INFOID:0000000003532251
1.CHECK STARTING OUT FROM D1
1. Drive the vehicle for about 10 minutes to warm up the engine oil and ATF.
Appropriate temperature for the ATF: 50 - 80°C (122 - 176°F)
2. Park the vehicle on a level surface.
3. Move selector lever to “P” position.
4. Start the engine.
5. Move selector lever to “D” position.

AT-80
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
56
OthersMaximum speed low.ON vehicle1. Fluid level and stateAT- 5 1
2. Line pressure testAT- 5 1
3. Accelerator pedal position sensorAT- 11 7
4. CAN communication lineAT- 9 1
5. Direct clutch solenoid valveAT- 1 3 8
6. Control valve with TCMAT- 2 1 0
OFF vehicle7. Torque converterAT- 2 4 0
8. Oil pump assemblyAT- 2 5 8
9. Input clutchAT- 2 6 2
10. Gear systemAT- 2 2 8
11. High and low reverse clutchAT- 2 7 2
12. Direct clutchAT- 2 7 4
13. 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
14 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
57 Extremely large creep.ON vehicle1. Engine idle speed EC-75

2. CAN communication lineAT- 9 1
3. ATF pressure switch 5AT- 1 5 4
OFF vehicle 4. Torque converterAT- 2 4 0
58With selector lever in
“P” position, vehicle
does not enter parking
condition or, with se-
lector lever in another
position, parking con-
dition is not cancelled.
Refer to AT-168, "
In
"P" Position, Vehicle
Moves When
Pushed".ON vehicle1. PNP switchAT- 9 9
2. Control cable adjustmentAT- 2 0 8
OFF vehicle 3. Parking pawl componentsAT- 2 2 8
59Vehicle runs with
transmission in “P” po-
sition.ON vehicle1. PNP switchAT- 9 9
2. Fluid level and stateAT- 5 1
3. Control cable adjustmentAT- 2 0 8
4. Control valve with TCMAT- 2 1 0
5. Parking pawl componentsAT- 2 2 8
OFF vehicle 6. Gear systemAT- 2 2 8
No. Items Symptom Condition Diagnostic ItemReference
page

AT-202
< SERVICE INFORMATION >
A/T SHIFT LOCK SYSTEM
A/T SHIFT LOCK SYSTEM
DescriptionINFOID:0000000003532469
• The electrical key interlock mechanism also operates as a shift lock:
With the ignition switch turned to ON, the selector lever cannot be shifted from “P” (parking) to any other
position unless the brake pedal is depressed.
With the key removed, the selector lever cannot be shifted from “P” to any other position.
The key cannot be removed unless the selector lever is placed in “P”.
• The shift lock and key interlock mechanisms are controlled by the ON-OFF operation of the shift lock sole-
noid and by the operation of the rotator and slider located inside the key cylinder, respectively.
Shift Lock System Electrical Parts LocationINFOID:0000000003532470
LCIA0326E

OVERHAUL
AT-231
< SERVICE INFORMATION >
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2WD models
13. Snap ring 14. Spring retainer 15. Return spring
16. Reverse brake piston 17. D-ring 18. D-ring
AWDIA0027GB
1. Rear oil seal 2. Bracket 3. Bracket
4. Adapter case 5. Parking actuator support 6. Parking pawl
7. Return spring 8. Pawl shaft 9. Self-sealing bolt
10. Bracket 11. Seal ring 12. Needle bearing

BR-8
< SERVICE INFORMATION >
BRAKE FLUID
BRAKE FLUID
On Board InspectionINFOID:0000000003532724
LEVEL CHECK
• Make sure the fluid level in reservoir tank is within the standard
(between MAX and MIN lines).
• Visually check around reservoir tank for fluid leaks.
• If fluid level is excessively low, check brake system for leaks.
• If brake warning lamp remains illuminated after parking lever is
released, check brake system for fluid leakage.
Drain and RefillINFOID:0000000003532725
CAUTION:
• Refill with new brake fluid. Refer to MA-10
.
• Do not reuse drained brake fluid.
• Do not let brake fluid splash on the painted surfaces of the body. This might damage the paint, so
when splashing it, immediately wipe off the area and wash away with water.
• Before servicing, disconnect actuator connector or battery negative cable.
1. Connect a vinyl tube to each bleed valve.
2. Depress brake pedal, loosen each bleed valve, and gradually
remove brake fluid.
3. Make sure there is no foreign material in reservoir tank, and refill
with new brake fluid.
4. Rest foot on brake pedal. Loosen bleed valve. Slowly depress
pedal until it stops. Tighten bleed valve. Release brake pedal.
Repeat this process a few times, then pause to add new brake
fluid to master cylinder. Continue until new brake fluid flows out.
Bleed air from brake system. Refer to BR-8, "
Bleeding Brake
System" .
Bleeding Brake SystemINFOID:0000000003532726
CAUTION:
While bleeding, pay attention to master cylinder fluid level.
1. Turn ignition switch OFF and disconnect ABS actuator and electric unit (control unit) connector or battery
negative cable.
2. Connect a vinyl tube to the rear right bleed valve.
3. Fully depress brake pedal 4 to 5 times.
LFIA0225E
SBR419C
SBR995