2006 INFINITI QX56 engine

AT-58
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
6. CHECK LOCK-UP
When releasing accelerator pedal from D5, check lock-up from D5 to L/U.

Refer to AT- 6 0 , "Vehicle Speed When Shifting Gears" .
With CONSULT-II
Select “TCC SOLENOID 0.00A ” with the “MAIN SIGNAL ” mode for A/T.
Does it lock-up?
YES >> GO TO 7.
NO >> Enter a check mark at “A/T Does Not Perform Lock-up” on the diagnostics worksheet, then con-
tinue the road test.
7. CHECK LOCK-UP HOLD
Does it maintain lock-up status?
YES >> GO TO 8.
NO >> Enter a check mark at “A/T Does Not Hold Lock-up Condition ” on the diagnostics worksheet, then
continue the road test.
8. CHECK LOCK-UP RELEASE
Check lock-up cancellation by depressing brake pedal lightly to decelerate. With CONSULT-II
Select “TCC SOLENOID 0.00A ” with the “MAIN SIGNAL ” mode for A/T.
Does lock-up cancel?
YES >> GO TO 9.
NO >> Enter a check mark at “Lock-up Is Not Released” on the diagnostics worksheet, then continue the
road test.
9. CHECK SHIFT-DOWN D5 → D4
Decelerate by pressing lightly on the brake pedal. With CONSULT-II
Read the gear position and engine speed.
When the A/T shift-down D5
→ D4, does the engine speed drop smoothly back to idle?
YES >> 1. Stop the vehicle.
2. Go to Cruise test - Part 2 (Refer to AT- 5 8
).
NO >> Enter a check mark at “Engine Speed Does Not Return to Idle” on the diagnostics worksheet, then continue the road test. Go to Cruise test - Part 2 (Refer to AT- 5 8
).
Cruise Test - Part 2ECS00CEI
1. CHECK STARTING FROM D1
1. Move selector lever the “D ” position.
2. Accelerate at half throttle.
With CONSULT-II
Read the gear position.
Does it start 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 DIAGNOSISAT-59
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Revision: November 2009 2006 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- 6 0 , "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- 6 0 , "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- 5 9 , "
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- 8 6 , "
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.

TROUBLE DIAGNOSISAT-61
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Revision: November 2009 2006 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- 5 1 , "A/T FLUID
CHECK" .
No. Items Symptom Condition Diagnostic ItemReference
page
1
Shift
Shock Large shock. (
“N ” → “
D ” position)
Refer to AT-182,
"Large Shock (“N” to
“D” Position)" . ON vehicle 1. Engine idle speed
EC-76
2. Engine speed signalAT- 11 6
3. Accelerator pedal position sensorAT-124
4. Control cable adjustmentAT-227
5. ATF temperature sensorAT-127
6. ATF pressure switch 1 and front brake solenoid valveAT-159,
AT-143
7. CAN communication line AT- 9 6
8. Fluid level and stateAT- 5 1
9. Line pressure testAT- 5 2
10. Control valve with TCMAT-230
OFF vehicle11. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7 , AT- 1 8
.) AT-264
2Shock is too large
when changing D1 →

D
2 . ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. ATF pressure switch 5 and direct clutch solenoid valveAT-163,
AT-147
4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT-109
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT-230
OFF vehicle 10. Direct clutch AT-298
3Shock is too large
when changing D2 →

D
3 . ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT-165,
AT-151
4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT-109
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT-230
OFF vehicle 10. High and low reverse clutch AT-296

AT-62
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
4
Shift
Shock Shock is too large
when changing D3
→
D
4 . ON vehicle1. Accelerator pedal position sensor
AT- 1 2 4
2. Control cable adjustmentAT- 2 2 7
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 6 1,
AT- 1 3 9
4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT- 1 0 9
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT- 2 3 0
OFF vehicle 10. Input clutch AT- 2 8 6
5Shock is too large
when changing D4
→
D
5 . ON vehicle1. Accelerator pedal position sensor
AT- 1 2 4
2. Control cable adjustmentAT- 2 2 7
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 5 9,
AT- 1 4 3

4. CAN communication line AT- 9 6
5. Engine speed signalAT- 11 6
6. Turbine revolution sensorAT- 1 0 9
7. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT- 2 3 0
OFF vehicle10. Front brake (brake band)
AT- 2 5 011. Input clutchAT- 2 8 6
6Shock is too large for
downshift when accel-
erator pedal is
pressed. ON vehicle1. Accelerator pedal position sensor
AT- 1 2 4
2. Control cable adjustmentAT- 2 2 7
3. CAN communication line AT- 9 6
4. Engine speed signalAT- 11 6
5. Turbine revolution sensorAT- 1 0 9
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2
7. Fluid level and state AT- 5 1
8. Control valve with TCMAT- 2 3 0
OFF vehicle9. Front brake (brake band)
AT- 2 5 0
10. Input clutchAT- 2 8 6
11. High and low reverse clutchAT- 2 9 6AT-
296
12. Direct clutch
AT- 2 9 8
No. ItemsSymptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSISAT-63
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Revision: November 2009 2006 QX56
7
Shift
Shock Shock is too large for
upshift when acceler-
ator pedal is released.
ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. Engine speed signal AT- 11 6
4. CAN communication line AT- 9 6
5. Turbine revolution sensorAT-109
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
7. Fluid level and state AT- 5 1
8. Control valve with TCMAT-230
OFF vehicle9. Front brake (brake band)
AT-25010. Input clutchAT-286
11. High and low reverse clutchAT-296
12. Direct clutchAT-298
8Shock is too large for
lock-up. ON vehicle1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. Engine speed signal AT- 11 6
4. CAN communication line AT- 9 6
5. Turbine revolution sensorAT-109
6. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
7. Torque converter clutch solenoid valve AT- 11 8
8. Fluid level and state AT- 5 1
9. Control valve with TCMAT-230
OFF vehicle 10. Torque converter AT-264
9Shock is too large
during engine brake. ON vehicle
1. Accelerator pedal position sensor
AT-124
2. Control cable adjustmentAT-227
3. CAN communication line AT- 9 6
4. Fluid level and stateAT- 5 1
5. Control valve with TCMAT-230
OFF vehicle6. Front brake (brake band)
AT-2507. Input clutchAT-286
8. High and low reverse clutchAT-296
9. Direct clutchAT-298
No. ItemsSymptom Condition Diagnostic ItemReference
page

AT-68
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
22
Slips/Will
Not
Engage When
“D ” position,
remains in 5th gear. ON vehicle1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT- 1 3 2

3. ATF pressure switch 1 and front brake solenoid valve AT- 1 5 9
,
AT- 1 4 3
4. Line pressure test AT- 5 2
5. CAN communication lineAT- 9 6
6. Control valve with TCMAT- 2 3 0
OFF vehicle7. Front brake (brake band)
AT- 2 6 48. Input clutchAT- 2 8 6
9. Gear systemAT- 2 5 0
10. High and low reverse clutchAT- 2 9 6
23Vehicle cannot be
started from D
1 .
Refer to AT-191, "
Vehi-
cle Cannot Be Started
From D1" . ON vehicle
1. Fluid level and state
AT- 5 1
2. Accelerator pedal position sensorAT- 1 2 4
3. Line pressure test AT- 5 2
4. CAN communication lineAT- 9 6
5. Control valve with TCMAT- 2 3 0
OFF vehicle6. Torque converter
AT- 2 6 4
7. Oil pump assemblyAT- 2 8 2
8. 3rd one-way clutchAT- 2 8 4
9. 1st one-way clutchAT- 2 9 1
10. Gear systemAT- 2 5 0
11. Reverse brakeAT- 2 6 4
12. Forward one-way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8 .) AT- 2 6 4
13. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to
AT- 1 7
, AT- 1 8
.) AT- 2 6 4
24Does not lock-up.
Refer to
AT-203, "A/T
Does Not Perform
Lock-up" . ON vehicle1. Fluid level and state
AT- 5 1
2. Line pressure testAT- 5 2
3. Engine speed signalAT- 11 6
4. Turbine revolution sensorAT- 1 0 9
5. Torque converter clutch solenoid valve AT- 11 8
6. CAN communication line AT- 9 6
7. Control valve with TCMAT- 2 3 0
OFF vehicle8. Torque converter
AT- 2 6 49. Oil pump assemblyAT- 2 8 2
No. ItemsSymptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSISAT-69
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Revision: November 2009 2006 QX5625
Slips/Will
Not
engage Does not hold lock-up
condition.
Refer to
AT-205, "A/T
Does Not Hold Lock-
up Condition" . ON vehicle 1. Fluid level and state
AT- 5 1
2. Line pressure testAT- 5 2
3. Engine speed signalAT- 11 6
4. Turbine revolution sensorAT-109
5. Torque converter clutch solenoid valve AT- 11 8
6. CAN communication line AT- 9 6
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-2649. Oil pump assemblyAT-282
26Lock-up is not
released.
Refer to
AT-207,
"Lock-up Is Not
Released" . ON vehicle1. Fluid level and state
AT- 5 1
2. Line pressure testAT- 5 2
3. Engine speed signalAT- 11 6
4. Turbine revolution sensorAT-109
5. Torque converter clutch solenoid valve AT- 11 8
6. CAN communication line AT- 9 6
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-2649. Oil pump assemblyAT-282
27No shock at all or the
clutch slips when
vehicle changes
speed D
1 →
D2 . ON vehicle
1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
3. ATF pressure switch 5 and direct clutch solenoid valve AT-163,
AT-147
4. CAN communication line AT- 9 6
5. Line pressure testAT- 5 2
6. Control valve with TCMAT-230
OFF vehicle7. Torque converter
AT-264
8. Oil pump assemblyAT-282
9. 3rd one-way clutchAT-284
10. Gear systemAT-250
11. Direct clutchAT-298
12. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 7
, AT- 1 8
.) AT-264
No. Items
Symptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSISAT-71
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Revision: November 2009 2006 QX56
30
Slips/Will
Not
engage No shock at all or the
clutch slips when
vehicle changes
speed D
4 →
D5 . ON vehicle 1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
3. ATF pressure switch 1 and front brake solenoid valve AT-159,
AT-143
4. ATF pressure switch 5 and direct clutch solenoid valve AT-163,
AT-147
5. CAN communication line AT- 9 6
6. Line pressure testAT- 5 2
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-264
9. Oil pump assemblyAT-282
10. Front brake (brake band)AT-264
11. Input clutchAT-286
12. Gear systemAT-250
13. High and low reverse clutchAT-296
31When you press the
accelerator pedal and
shift speed D5 →
D4
the engine idles or the
transmission slips. ON vehicle
1. Fluid level and state
AT- 5 1
2. Vehicle speed sensor A/T and vehicle speed sensor MTRAT- 111,
AT-132
3. ATF pressure switch 1 and front brake solenoid valve AT-159,
AT-143
4. ATF pressure switch 5 and direct clutch solenoid valve AT-163,
AT-147
5. CAN communication line AT- 9 6
6. Line pressure testAT- 5 2
7. Control valve with TCMAT-230
OFF vehicle8. Torque converter
AT-264
9. Oil pump assemblyAT-282
10. Input clutchAT-286
11. Gear systemAT-250
12. High and low reverse clutchAT-296
13. Direct clutchAT-298
No. ItemsSymptom Condition Diagnostic ItemReference
page