2004 INFINITI QX56 parking brake

AT-30
A/T CONTROL SYSTEM
Revision: August 20072004 QX56
“R” Position

The front brake fastens the front sun gear.

The high and low reverse clutch is coupled, and the mid sun gear and rear sun gear are connected.

The reverse brake fastens the rear carrier.
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
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AT-58
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Inspections Before Trouble DiagnosisUCS002CX
A/T FLUID CHECK
Fluid Leakage and Fluid Level Check

Inspect for fluid leakage and check the fluid level. Refer to AT - 1 3 , "Checking A/T Fluid" .
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.
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
places where water is getting in.
Large amount of
metal powder mixed
inUnusual wear of
sliding parts within
A/TReplace the ATF and check for
improper operation of the A/T.
SAT6 3 8A
SAT6 4 7B
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SAT5 1 4G

AT-60
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
3. After warming up remove the oil pressure detection plug and
install the oil pressure gauge [ST2505S001(J34301-C)].
CAUTION:
When using the oil pressure gauge, be sure to use the O-
ring attached to the oil pressure detection plug.
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 AT-5 8, "
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
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:7.3 N·m (0.74 kg-m, 65 in-lb)SAT4 9 3G
Engine speedLine pressure [kPa (kg/cm
2 , psi)]
R position D position
At idle speed 392 - 441 (4.0 - 4.5, 57 - 64) 373 - 422 (3.8 - 4.3, 54 - 61)
At stall speed 1,700 - 1,890 (17.3 - 19.3, 247 - 274) 1,310 - 1,500 (13.3 - 15.3, 190 - 218)

AT-62
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Check Before Engine is StartedUCS002CY
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 >> GO TO 2.
NO >> Stop the road test and go to AT-191, "
AT CHECK Indicator Lamp Does Not Come On" .
2. CHECK AT CHECK INDICATOR LAMP
Does AT CHECK indicator lamp flash for about 8 seconds?
YES >> For TCM fail-safe mode, carry out self-diagnostics and record all NG items on the diagnostics
worksheet. Refer to AT - 9 3
.
NO >> 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 - 9 3
.
3. Go to AT- 6 2 , "
Check at Idle" .
Check at Idle UCS002CZ
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-192, "
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.
3. Turn ignition switch to “START” position.
Does the engine start in either position?
YES >> Stop the road test and go to AT-192, "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 “Vehicle moves when pushed in “P” position” on the diagnostics worksheet,
then continue the road test.
NO >> GO TO 4.

TROUBLE DIAGNOSIS
AT-63
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Revision: August 20072004 QX56
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 “Vehicle moves in “N” position” on the diagnostics worksheet, then continue
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 when shifted from N to D” on the diagnostics worksheet, then
continue the road test.
NO >> GO TO 6.
6. CHECK “R” POSITION FUNCTIONS
1. Engage the brake.
2. Move selector lever to “R” position.
3. Disengage 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 work-
sheet, then continue the road test.
7. CHECK “D” POSITION FUNCTIONS
Inspect whether the vehicle moves forward when the transmission is put into the “D” position.
Does the vehicle creep forward in the
“D” positions?
YES >> Go to AT- 6 3 , "Cruise Test - Part 1" , AT- 6 5 , "Cruise Test - Part 2" , and AT- 6 6 , "Cruise Test - Part
3" .
NO >> Enter a check mark at “Vehicle does not move forward in D positions” on the diagnostics work-
sheet, then continue the road test.
Cruise Test - Part 1UCS002D0
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.
6. Press the accelerator pedal about half way down to accelerate the vehicle.
With CONSULT-II
Read off the gear positions.
Starts from D1?
YES >> GO TO 2.
NO >> Enter a check mark at “Vehicle cannot be started from D1” on the diagnostics worksheet, then
continue the road test.

TROUBLE DIAGNOSIS
AT-87
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AT
Revision: August 20072004 QX56
56
OthersMaximum speed low.ON vehicle1. Fluid level and stateAT- 5 8
2. Line pressure testAT- 5 9
3. Accelerator pedal position sensorAT- 1 2 9
4. CAN communication lineAT- 1 0 3
5. Direct clutch solenoid valveAT- 1 5 7
6. Control valve with TCMAT- 2 4 1
OFF vehicle7. Torque converterAT- 2 7 3
8. Oil pump assemblyAT- 2 9 0
9. Input clutchAT- 2 9 5
10. Gear systemAT- 2 6 1
11. High and low reverse clutchAT- 3 0 5
12. Direct clutchAT- 3 0 7
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 8
, AT-1 9 .)AT- 2 7 3
14 Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-1 8
, AT - 1 9
.)AT- 2 7 3
57Extremely large
creep.ON vehicle1. Engine idle speed EC-32

2. CAN communication lineAT- 1 0 3
3. ATF pressure switch 5AT- 1 8 1
OFF vehicle 4. Torque converterAT- 2 7 3
58With selector lever in
“P” position, vehicle
does not enter parking
condition or, with
selector lever in
another position, park-
ing condition is not
cancelled.
Refer to AT- 1 9 3 , "
In
“P” Position, Vehicle
Moves When Pushed"
.ON vehicle1. PNP switchAT- 1 0 9
2. Control cable adjustmentAT- 2 3 4
3. Parking pawl componentsAT- 2 6 1
59Vehicle runs with
transmission in “P”
position.ON vehicle1. PNP switchAT- 1 0 9
2. Fluid level and stateAT- 5 8
3. Control cable adjustmentAT- 2 3 4
4. Control valve with TCMAT- 2 4 1
5. Parking pawl componentsAT- 2 6 1
OFF vehicle 6. Gear systemAT- 2 6 1
No. Items Symptom Condition Diagnostic ItemReference
page

AT-236
A/T SHIFT LOCK SYSTEM
Revision: August 20072004 QX56
A/T SHIFT LOCK SYSTEMPFP:34950
DescriptionUCS002J 6

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 LocationUCS002J 7
LCIA0326E

AT-284
DISASSEMBLY
Revision: August 20072004 QX56
43. Remove parking gear from output shaft.
44. Remove seal rings from output shaft.
45. Remove needle bearing from transmission case.
46. Remove revolution sensor from transmission case.
CAUTION:

Do not subject it to impact by dropping or hitting it.

Be careful not to damage harness with the edge of case.

Do not allow metal filings, etc., to get on the sensor's
front edge magnetic area.

Do not place in an area affected by magnetism.
47. Remove reverse brake snap ring (fixing plate) using 2 flat-
bladed screwdrivers.
NOTE:
Press out snap ring from the transmission case oil pan side gap
using a flat-bladed screwdriver, and remove it using another
screwdriver.
48. Remove reverse brake retaining plate from transmission case.
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