2005 INFINITI QX4 engine

AT-58
TROUBLE DIAGNOSIS
Revision: October 20052005 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-59, "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-59, "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-58, "
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 3ECS00CEJ
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-85, "
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-60
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Symptom ChartECS00CEN

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-50, "A/T FLUID
CHECK" .
No. Items Symptom Condition Diagnostic ItemReference
page
1
Shift
ShockLarge shock. (“N” →“
D” position)
Refer to AT-183,
"Large Shock (“N” to
“D” Position)" .ON vehicle1. Engine idle speedEC-77
2. Engine speed signalAT - 11 3
3. Accelerator pedal position sensorAT- 1 2 3
4. Control cable adjustmentAT- 2 2 8
5. ATF temperature sensorAT- 1 2 6
6. ATF pressure switch 1 and front brake solenoid valveAT- 1 6 0,
AT- 1 4 4
7. CAN communication lineAT-9 5
8. Fluid level and stateAT-5 0
9. Line pressure testAT-5 1
10. Control valve with TCMAT- 2 3 1
OFF vehicle11. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-1 6 , AT- 1 7
.)AT- 2 6 2
2Shock is too large
when changing D1 →
D
2 .ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 6 4,
AT- 1 4 8
4. CAN communication lineAT-9 5
5. Engine speed signalAT - 11 3
6. Turbine revolution sensorAT- 1 3 1
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
8. Fluid level and stateAT-5 0
9. Control valve with TCMAT- 2 3 1
OFF vehicle 10. Direct clutchAT- 2 9 6
3Shock is too large
when changing D2 →
D
3 .ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 6 6,
AT- 1 5 2
4. CAN communication lineAT-9 5
5. Engine speed signalAT - 11 3
6. Turbine revolution sensorAT- 1 3 1
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
8. Fluid level and stateAT-5 0
9. Control valve with TCMAT- 2 3 1
OFF vehicle 10. High and low reverse clutchAT- 2 9 4

TROUBLE DIAGNOSIS
AT-61
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: October 20052005 QX56
4
Shift
ShockShock is too large
when changing D3 →
D
4 .ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 6 2,
AT- 1 4 0
4. CAN communication lineAT- 9 5
5. Engine speed signalAT- 11 3
6. Turbine revolution sensorAT- 1 3 1
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
8. Fluid level and stateAT- 5 0
9. Control valve with TCMAT- 2 3 1
OFF vehicle 10. Input clutchAT- 2 8 4
5Shock is too large
when changing D4 →
D
5 .ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 6 0,
AT- 1 4 4

4. CAN communication lineAT- 9 5
5. Engine speed signalAT- 11 3
6. Turbine revolution sensorAT- 1 3 1
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
8. Fluid level and stateAT- 5 0
9. Control valve with TCMAT- 2 3 1
OFF vehicle10. Front brake (brake band)AT- 2 5 011. Input clutchAT- 2 8 4
6Shock is too large for
downshift when accel-
erator pedal is
pressed.ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. CAN communication lineAT- 9 5
4. Engine speed signalAT- 11 3
5. Turbine revolution sensorAT- 1 3 1
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
7. Fluid level and stateAT- 5 0
8. Control valve with TCMAT- 2 3 1
OFF vehicle9. Front brake (brake band)AT- 2 5 010. Input clutchAT- 2 8 4
11. High and low reverse clutchAT- 2 9 4
12. Direct clutchAT- 2 9 6
No. Items Symptom Condition Diagnostic ItemReference
page

AT-62
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
7
Shift
ShockShock is too large for
upshift when acceler-
ator pedal is released.ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. Engine speed signalAT - 11 3
4. CAN communication lineAT-9 5
5. Turbine revolution sensorAT- 1 3 1
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
7. Fluid level and stateAT-5 0
8. Control valve with TCMAT- 2 3 1
OFF vehicle9. Front brake (brake band)AT- 2 5 010. Input clutchAT- 2 8 4
11. High and low reverse clutchAT- 2 9 4
12. Direct clutchAT- 2 9 6
8Shock is too large for
lock-up.ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. Engine speed signalAT - 11 3
4. CAN communication lineAT-9 5
5. Turbine revolution sensorAT- 1 3 1
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
7. Torque converter clutch solenoid valveAT - 11 5
8. Fluid level and stateAT-5 0
9. Control valve with TCMAT- 2 3 1
OFF vehicle 10. Torque converterAT- 2 6 2
9Shock is too large
during engine brake.ON vehicle1. Accelerator pedal position sensorAT- 1 2 3
2. Control cable adjustmentAT- 2 2 8
3. CAN communication lineAT-9 5
4. Fluid level and stateAT-5 0
5. Control valve with TCMAT- 2 3 1
OFF vehicle6. Front brake (brake band)AT- 2 5 07. Input clutchAT- 2 8 4
8. High and low reverse clutchAT- 2 9 4
9. Direct clutchAT- 2 9 6
No. Items Symptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSIS
AT-67
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: October 20052005 QX56
22
Slips/Will
Not
EngageWhen “D” position,
remains in 5th gear.ON vehicle1. Fluid level and stateAT- 5 0
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3

3. ATF pressure switch 1 and front brake solenoid valveAT- 1 6 0
,
AT- 1 4 4
4. Line pressure testAT- 5 1
5. CAN communication lineAT- 9 5
6. Control valve with TCMAT- 2 3 1
OFF vehicle7. Front brake (brake band)AT- 2 6 28. Input clutchAT- 2 8 4
9. Gear systemAT- 2 5 0
10. High and low reverse clutchAT- 2 9 4
23Vehicle cannot be
started from D
1 .
Refer toAT- 1 9 2 , "
Vehi-
cle Cannot Be Started
From D1" .ON vehicle1. Fluid level and stateAT- 5 0
2. Accelerator pedal position sensorAT- 1 2 3
3. Line pressure testAT- 5 1
4. CAN communication lineAT- 9 5
5. Control valve with TCMAT- 2 3 1
OFF vehicle6. Torque converterAT- 2 6 2
7. Oil pump assemblyAT- 2 8 0
8. 3rd one-way clutchAT- 2 8 2
9. 1st one-way clutchAT- 2 8 9
10. Gear systemAT- 2 5 0
11. Reverse brakeAT- 2 6 2
12. Forward one-way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 6
, AT-1 7 .)AT- 2 6 2
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 6
, AT- 1 7
.)AT- 2 6 2
24Does not lock-up.
Refer to AT- 2 0 4 , "A/T
Does Not Perform
Lock-up" .ON vehicle1. Fluid level and stateAT- 5 0
2. Line pressure testAT- 5 1
3. Engine speed signalAT- 11 3
4. Turbine revolution sensorAT- 1 3 1
5. Torque converter clutch solenoid valveAT- 11 5
6. CAN communication lineAT- 9 5
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converterAT- 2 6 29. Oil pump assemblyAT- 2 8 0
No. Items Symptom Condition Diagnostic ItemReference
page

AT-68
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
25
Slips/Will
Not
engageDoes not hold lock-up
condition.
Refer toAT- 2 0 6 , "A/T
Does Not Hold Lock-
up Condition" .ON vehicle1. Fluid level and stateAT-5 0
2. Line pressure testAT-5 1
3. Engine speed signalAT - 11 3
4. Turbine revolution sensorAT- 1 3 1
5. Torque converter clutch solenoid valveAT - 11 5
6. CAN communication lineAT-9 5
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converterAT- 2 6 29. Oil pump assemblyAT- 2 8 0
26Lock-up is not
released.
Refer toAT- 2 0 8 ,
"Lock-up Is Not
Released" .ON vehicle1. Fluid level and stateAT-5 0
2. Line pressure testAT-5 1
3. Engine speed signalAT - 11 3
4. Turbine revolution sensorAT- 1 3 1
5. Torque converter clutch solenoid valveAT - 11 5
6. CAN communication lineAT-9 5
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converterAT- 2 6 29. Oil pump assemblyAT- 2 8 0
27No shock at all or the
clutch slips when
vehicle changes
speed D
1 → D2 . ON vehicle1. Fluid level and stateAT-5 0
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
3. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 6 4,
AT- 1 4 8
4. CAN communication lineAT-9 5
5. Line pressure testAT-5 1
6. Control valve with TCMAT- 2 3 1
OFF vehicle7. Torque converterAT- 2 6 2
8. Oil pump assemblyAT- 2 8 0
9. 3rd one-way clutchAT- 2 8 2
10. Gear systemAT- 2 5 0
11. Direct clutchAT- 2 9 6
12. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-1 6
, AT- 1 7
.)AT- 2 6 2
No. Items Symptom Condition Diagnostic ItemReference
page

AT-70
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
30
Slips/Will
Not
engageNo shock at all or the
clutch slips when
vehicle changes
speed D
4 → D5 .ON vehicle1. Fluid level and stateAT-5 0
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 6 0,
AT- 1 4 4
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 6 4,
AT- 1 4 8
5. CAN communication lineAT-9 5
6. Line pressure testAT-5 1
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converterAT- 2 6 2
9. Oil pump assemblyAT- 2 8 0
10. Front brake (brake band)AT- 2 6 2
11. Input clutchAT- 2 8 4
12. Gear systemAT- 2 5 0
13. High and low reverse clutchAT- 2 9 4
31When you press the
accelerator pedal and
shift speed D5 → D4
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT-5 0
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 6 0,
AT- 1 4 4
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 6 4,
AT- 1 4 8
5. CAN communication lineAT-9 5
6. Line pressure testAT-5 1
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converterAT- 2 6 2
9. Oil pump assemblyAT- 2 8 0
10. Input clutchAT- 2 8 4
11. Gear systemAT- 2 5 0
12. High and low reverse clutchAT- 2 9 4
13. Direct clutchAT- 2 9 6
No. Items Symptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSIS
AT-71
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: October 20052005 QX56
32
Slips/Will
Not
engageWhen you press the
accelerator pedal and
shift speed D4 → D3
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT- 5 0
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 6 2,
AT- 1 4 0
4. ATF pressure switch 1 and front brake solenoid valveAT- 1 6 0,
AT- 1 4 4
5. CAN communication lineAT- 9 5
6. Line pressure testAT- 5 1
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converter AT- 2 6 2
9. Oil pump assemblyAT- 2 8 0
10. 3rd one-way clutchAT- 2 8 2
11. Gear systemAT- 2 5 0
12. High and low reverse clutchAT- 2 9 4
13. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 6
, AT-1 7 .)AT- 2 6 2
14. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 6
, AT- 1 7
.)AT- 2 6 2
33When you press the
accelerator pedal and
shift speed D3 → D2
the engine idles or the
transmission slips.ON vehicle1. Fluid level and stateAT- 5 0
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 1 0 8,
AT- 1 3 3
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT- 1 6 6,
AT- 1 5 2
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 6 4,
AT- 1 4 8
5. CAN communication lineAT- 9 5
6. Line pressure testAT- 5 1
7. Control valve with TCMAT- 2 3 1
OFF vehicle8. Torque converterAT- 2 6 2
9. Oil pump assemblyAT- 2 8 0
10. 3rd one-way clutchAT- 2 8 2
11. Gear systemAT- 2 5 0
12. Direct clutchAT- 2 9 6
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 6
, AT- 1 7
.)AT- 2 6 2
No. Items Symptom Condition Diagnostic ItemReference
page