2004 INFINITI QX56 Ins

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
SCIA0504E
SCIA1224E
: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)

TROUBLE DIAGNOSIS
AT-61
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Judgement of Line Pressure Test
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 - 6 2
.
2. Check at idle. Refer to AT- 6 2
.
3. Cruise test

Inspect all the items from Part 1 to Part 3. Refer to AT- 6 3 , AT- 6 5 , AT- 6 6 .

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.
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
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.

TROUBLE DIAGNOSIS
AT-63
D
E
F
G
H
I
J
K
L
MA
B
AT
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.

AT-64
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
2. CHECK SHIFT-UP D1 → D2
Press down the accelerator pedal about half way and inspect if the vehicle shifts up (D1 → D2) at the appropri-
ate speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle degree of opening, and vehicle speed.
Does the A/T shift-up D1
→ D2 at the correct speed?
YES >> GO TO 3.
NO >> Enter a check mark at “A/T does not shift D1 → D2” on the diagnostics worksheet, then continue
the road test.
3. CHECK SHIFT-UP D2 → D3
Press down the accelerator pedal about half way and inspect if the vehicle shifts up (D2 → D3) at the appropri-
ate speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle degree of opening, and vehicle speed.
Does the A/T shift-up D2
→ D3 at the correct speed?
YES >> GO TO 4.
NO >> Enter a check mark at “A/T does not shift D2 → D3” on the diagnostics worksheet, then continue
the road test.
4. CHECK SHIFT-UP D3 → D4
Press down the accelerator pedal about half way and inspect if the vehicle shifts up (D3 → D4) at the appropri-
ate speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle degree of opening, and vehicle speed.
Does the A/T shift-up D3
→ D4 at the correct speed?
YES >> GO TO 5.
NO >> Enter a check mark at “A/T does not shift D3 → D4” on the diagnostics worksheet, then continue
the road test.
5. CHECK SHIFT-UP D4 → D5
Press down the accelerator pedal about half way and inspect if the vehicle shifts up (D4 → D5) at the appropri-
ate speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle degree of opening, and vehicle speed.
Does the A/T shift-up D4
→ D5 at the correct speed?
YES >> GO TO 6.
NO >> Enter a check mark at “A/T does not shift D4 → D5” on the diagnostics worksheet, then continue
the road test.

AT-66
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
2. CHECK SHIFT-UP D1 → D2
Press the accelerator pedal down all the way and inspect whether or not the transmission shifts up (D1 → D2)
at the correct speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle position and vehicle speed.
Does the A/T shift-up D1
→ D2 at the correct speed?
YES >> GO TO 3.
NO >> Enter a check mark at “Vehicle does not shift D1 → D2” on the diagnostics worksheet, then con-
tinue the road test.
3. CHECK SHIFT-UP D2 → D3
Press the accelerator pedal down all the way and inspect whether or not the transmission shifts up (D2 → D3)
at the correct speed.

Refer to AT-67, "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Read the gear position, throttle position and vehicle speed.
Does the A/T shift-up D2
→ D3 at the correct speed?
YES >> GO TO 4.
NO >> Enter a check mark at “Vehicle does not shift D2 → D3” on the diagnostics worksheet, then con-
tinue the road test.
4. CHECK SHIFT-UP D3 → D4 AND ENGINE BRAKE
When the transmission changes speed D3 → D4, return the accelerator pedal.
Does the A/T shift-up D3
→ D4 and apply the engine brake?
YES >> 1. Stop the vehicle.
2. See AT-66, "
Cruise Test - Part 3" .
NO >> Enter a check mark at “Vehicle does not shift D3 → D4” on the diagnostics worksheet, then con-
tinue the road test.
Cruise Test - Part 3UCS002D2
1. CHECK SHIFT-DOWN
During D
5 driving, move gear selector from D → 4 → 3 → 2 → 1.
With CONSULT-II
Read the gear position.
Is downshifting correctly performed?
YES >> GO TO 2.
NO >> Enter a check mark at “Vehicle does not shift” at the corresponding position (5th → 4th, 4th → 3rd,
3rd → 2nd, 2nd → 1st) on the diagnostics worksheet, then continue the road test.
2. CHECK ENGINE BRAKE
Does engine braking effectively reduce speed in 1
1 position?
YES >> 1. Stop the vehicle.
2. Carry out the self-diagnostics. Refer to AT-93, "
SELF-DIAGNOSTIC RESULT MODE" .
NO >> Enter a check mark at “Vehicle does not decelerate by engine brake” on the diagnostics work-
sheet, then continue trouble diagnosis.

AT-68
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Symptom ChartUCS002D6

The diagnostics item numbers show the sequence for inspection. Inspect in order from item 1.

Overhaul and inspect inside the A/T only if A/T fluid condition is NG. Refer to AT-58, "Fluid Condi-
tion Check" .
No. Items Symptom Condition Diagnostic ItemReference
page
1
Shift
ShockLarge shock. (“N” →“
D” position)
Refer to AT-195,
"Large Shock (“N” to
“D” Position)" .ON vehicle1. Engine idle speedEC-32
2. Engine speed signalAT - 11 5
3. Accelerator pedal position sensorAT- 1 2 9
4. Control cable adjustmentAT- 2 3 4
5. ATF temperature sensorAT- 1 3 1
6. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 5,
AT- 1 5 1
7. CAN communication lineAT- 1 0 3
8. Fluid level and stateAT-5 8
9. Line pressure testAT-5 9
10. Control valve with TCMAT- 2 4 2
OFF vehicle11. 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
2Shock is too large
when changing D1 →
D
2 .ON vehicle1. Accelerator pedal position sensorAT- 1 2 9
2. Control cable adjustmentAT- 2 3 4
3. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 8 1,
AT- 1 5 7
4. CAN communication lineAT- 1 0 3
5. Engine speed signalAT - 11 5
6. Turbine revolution sensorAT- 1 3 4
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
8. Fluid level and stateAT-5 8
9. Control valve with TCMAT- 2 4 1
OFF vehicle 10. Direct clutchAT- 3 0 7
3Shock is too large
when changing D2 →
D
3 .ON vehicle1. Accelerator pedal position sensorAT- 1 2 9
2. Control cable adjustmentAT- 2 3 4
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 8 4,
AT- 1 6 3
4. CAN communication lineAT- 1 0 3
5. Engine speed signalAT - 11 5
6. Turbine revolution sensorAT- 1 3 4
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
8. Fluid level and stateAT-5 8
9. Control valve with TCMAT- 2 4 1
OFF vehicle 10. High and low reverse clutchAT- 3 0 5

TROUBLE DIAGNOSIS
AT-73
D
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B
AT
Revision: August 20072004 QX56
18
Slips/Will
Not
engageWhen “D” position,
remains in 1st gear.ON vehicle1. Fluid level and stateAT- 5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. Direct clutch solenoid valveAT- 1 5 7
4. Line pressure testAT- 5 9
5. CAN communication lineAT- 1 0 3
6. Control valve with TCMAT- 2 4 1
OFF vehicle7. 3rd one-way clutchAT- 2 9 2
8. 1st one-way clutchAT- 3 0 0
9. Gear systemAT- 2 6 1
10. Reverse brakeAT- 2 7 3
11. 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
12. 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
19When “D” position,
remains in 2nd gear.ON vehicle1. Fluid level and stateAT- 5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTR AT- 11 2 ,
AT- 1 3 6
3. Low coast brake solenoid valveAT- 1 6 9
4. Line pressure testAT- 5 9
5. CAN communication lineAT- 1 0 3
6. Control valve with TCMAT- 2 4 1
OFF vehicle7. 3rd one-way clutchAT- 2 9 2
8. Gear systemAT- 2 6 1
9. Direct clutchAT- 3 0 7
10. 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
No. Items Symptom Condition Diagnostic ItemReference
page

AT-74
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
20
Slips/Will
Not
engageWhen “D” position,
remains in 3rd gear.ON vehicle1. Fluid level and stateAT-5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. Line pressure testAT-5 9
4. CAN communication lineAT- 1 0 3
5. Control valve with TCMAT- 2 4 1
OFF vehicle6. 3rd one-way clutchAT- 2 9 2
7. Gear systemAT- 2 6 1
8. High and low reverse clutchAT- 3 0 5
9. 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
10. 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
21When “D” position,
remains in 4th gear.ON vehicle1. Fluid level and stateAT-5 8
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 11 2,
AT- 1 3 6
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 7 8,
AT- 1 4 5
4. ATF pressure switch 5 and direct clutch solenoid valveAT-181,AT-
157
5. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 8 4
,
AT- 1 6 3
6. Low coast brake solenoid valveAT- 1 6 9
7. Front brake solenoid valveAT- 1 5 1
8. Line pressure testAT-5 9
9. CAN communication lineAT- 1 0 3
10. Control valve with TCMAT- 2 4 1
OFF vehicle11. Input clutchAT- 2 9 512. Gear systemAT- 2 6 1
13. High and low reverse clutchAT- 3 0 5
14. Direct clutchAT- 3 0 7
No. Items Symptom Condition Diagnostic ItemReference
page