2006 INFINITI QX56 check engine

AT-48
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
44-3Part 2
AT- 5 8
❏ AT-191, "Vehicle Cannot Be Started From D1"
❏ AT-194, "A/T Does Not Shift: D1 → D2"
❏ AT-196, "A/T Does Not Shift: D2 → D3"
❏ AT-198, "A/T Does Not Shift: D3 → D4"
Part 3
AT- 5 9
❏ AT-209, "A/T Does Not Shift: 5th gear → 4th gear"
❏ AT-212, "A/T Does Not Shift: 4th gear → 3rd gear"
❏ AT-213, "A/T Does Not Shift: 3rd gear → 2nd gear"
❏ AT-215, "A/T Does Not Shift: 2nd gear → 1st gear"
❏ AT-218, "Vehicle Does Not Decelerate By Engine Brake"
❏ Perform self-diagnostics Enter checks for detected items. AT- 8 6
❏ AT- 9 6 , "DTC U1000 CAN COMMUNICATION LINE"
❏ AT-100, "DTC P0615 START SIGNAL CIRCUIT"
❏ AT-104, "DTC P0700 TCM"
❏ AT-105, "DTC P0705 PARK/NEUTRAL POSITION SWITCH"
❏ AT-109, "DTC P0717 TURBINE REVOLUTION SENSOR"
❏ AT- 111 , "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)"
❏ AT- 11 6 , "DTC P0725 ENGINE SPEED SIGNAL"
❏ AT- 11 8 , "DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE"
❏ AT-120, "DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)"
❏ AT-122, "DTC P0745 LINE PRESSURE SOLENOID VALVE"
❏ AT-124, "DTC P1705 THROTTLE POSITION SENSOR"
❏ AT-127, "DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT"
❏ AT-132, "DTC P1721 VEHICLE SPEED SENSOR MTR"
❏ AT-134, "DTC P1730 A/T INTERLOCK"
❏ AT-137, "DTC P1731 A/T 1ST ENGINE BRAKING"
❏ AT-139, "DTC P1752 INPUT CLUTCH SOLENOID VALVE"
❏ AT-141, "DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-143, "DTC P1757 FRONT BRAKE SOLENOID VALVE"
❏ AT-145, "DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION"
❏ AT-147, "DTC P1762 DIRECT CLUTCH SOLENOID VALVE"
❏ AT-149, "DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION"
❏ AT-151, "DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE"
❏ AT-153, "DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION"
❏ AT-155, "DTC P1772 LOW COAST BRAKE SOLENOID VALVE"
❏ AT-157, "DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION"
❏ AT-159, "DTC P1841 ATF PRESSURE SWITCH 1"
❏ AT-161, "DTC P1843 ATF PRESSURE SWITCH 3"
❏ AT-163, "DTC P1845 ATF PRESSURE SWITCH 5"
❏ AT-165, "DTC P1846 ATF PRESSURE SWITCH 6"
5 ❏
Inspect each system for items found to be NG in the self-diagnostics and repair or replace the malfunction
parts.
6 ❏ Perform all road tests and enter the checks again for the required items. AT- 5 4
7❏
For any remaining NG items, perform the “diagnostics procedure ” and repair or replace the malfunction parts.
See the chart for diagnostics by symptoms. (This chart also contains other symptoms and inspection proce-
dures.) AT- 6 1
8
❏ Erase the results of the self-diagnostics from the TCM. AT- 3 9

TROUBLE DIAGNOSISAT-51
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Revision: November 2009 2006 QX56
Inspections Before Trouble DiagnosisECS00CEE
A/T FLUID CHECK
Fluid Leakage and Fluid Level Check

Inspect for fluid leakage and check the fluid level. Refer to AT- 1 2 , "Changing Automatic Transmission
Fluid (ATF)" .
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.
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
cloudy Water in the fluidReplace the ATF and check for
places where water is getting in.
Large amount of
metal powder mixed
in Unusual wear of
sliding parts within
A/T
Replace the ATF and check for
improper operation of the A/T.
SAT638A
SAT647B
SCIA1224E
SAT514G

AT-54
TROUBLE DIAGNOSIS
Revision: November 20092006 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- 5 5
.
2. Check at idle. Refer to AT- 5 5
.
3. Cruise test

Inspect all the items from Part 1 to Part 3. Refer to AT- 5 6 , AT- 5 8 , AT- 5 9 .

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 speed Low 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 position Possible causes include an oil pressure leak in a passage or device related to the position after
the pressure is distributed by the manual valve.
High Possible 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 speed Oil 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 position Possible 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 DIAGNOSISAT-55
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Revision: November 2009 2006 QX56
Check Before Engine is StartedECS00CEF
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 >> 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- 8 6
.
3. Go to AT- 5 5 , "
Check at Idle" .
NO >> Stop the road test and go to AT- 1 7 9 , "
A/T CHECK Indicator Lamp Does Not Come On" .
Check at Idle ECS00CEG
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- 1 7 9 , "
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- 1 7 9 , "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.

AT-56
TROUBLE DIAGNOSIS
Revision: November 20092006 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 “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- 5 6 , "Cruise Test - Part 1" , AT- 5 8 , "Cruise Test - Part 2" , and AT- 5 9 , "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 1ECS00CEH
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-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