2007 INFINITI QX56 torque

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
AT-113
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DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
DescriptionINFOID:0000000003532310
This malfunction is detected when the A/T does not shift into 5th gear position or the torque converter clutch
does not lock-up as instructed by the TCM. This is not only caused by electrical malfunction (circuits open or
shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation,
etc.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532311
On Board Diagnosis LogicINFOID:0000000003532312
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P0744 A/T TCC S/V FNCTN” with CONSULT-II is detected under the following con-
ditions.
- When A/T cannot perform lock-up even if electrical circuit is good.
- When TCM detects as irregular by comparing difference value with slip rotation.
Possible CauseINFOID:0000000003532313
• Harness or connectors
(The solenoid circuit is open or shorted.)
• Torque converter clutch solenoid valve
• Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003532314
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine and Select “TCC S/V FNCTN CHECK” of “DTC
WORK SUPPORT” mode for “A/T” with CONSULT-II and touch
“START”.
2. Accelerate vehicle to more than 80 km/h (50 MPH) and maintain
the following condition continuously until “TESTING” has turned
to “COMPLETE”. (It will take approximately 30 seconds after
“TESTING” shows.)
ACCELE POSI: More than 1.0/8 (at all times during step 4)
TCC SOLENOID: 0.4 - 0.6 A
Selector lever: “D” position
[Reference speed: Constant speed of more than 80 km/h (50
MPH)]
-Make sure “GEAR” shows “5”.
-For shift schedule, refer to AT-299, "
Vehicle Speed When Performing and Releasing Complete
Lock-up".
-If “TESTING” does not appear on CONSULT-II for a long time, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0744 is shown, refer to applicable “TROUBLE DIAGNOSIS FOR
DTC”.
3. Make sure that “OK” is displayed. (If “NG” is displayed, refer to “DIAGNOSTIC PROCEDURE”.)
Refer to AT-114, "
Diagnosis Procedure".
Item name Condition Display value (Approx.)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
BCIA0031E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-187
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2. Check A/T fluid condition. Refer to AT-51, "Inspections Before
Trouble Diagnosis".
OK or NG
OK >> GO TO 8.
NG >> GO TO 11.
8.DETECT MALFUNCTIONING ITEM
• Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-60,
"Symptom Chart" (Symptom No.13).
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
9.CHECK SYMPTOM
Check again. Refer to AT-55, "
Check at Idle".
OK or NG
OK >>INSPECTION END
NG >> GO TO 10.
10.PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-82, "
TCM Input/Output Signal Reference
Va l u e".
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
11 .DETECT MALFUNCTIONING ITEM
• Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-60,
"Symptom Chart" (Symptom No.13).
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
A/T Does Not Perform Lock-upINFOID:0000000003532460
SYMPTOM:
A/T does not perform lock-up at the specified speed.
DIAGNOSTIC PROCEDURE
1.CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT-83, "
CONSULT-II Function (A/T)".
Do the self-diagnostic results indicate torque converter clutch solenoid valve, engine speed signal, turbine rev-
olution sensor, accelerator pedal position sensor, CAN communication?
YES >> Check the malfunctioning system. Refer to AT- 111, AT-109' AT-103' AT- 11 7' AT- 9 1.
NO >> GO TO 2.
2.CHECK A/T FLUID LEVEL
SCIA5199E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-189
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2. Check A/T fluid condition. Refer to AT-51, "Inspections Before
Trouble Diagnosis".
OK or NG
OK >> GO TO 7.
NG >> GO TO 10.
7.DETECT MALFUNCTIONING ITEM
• Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-60,
"Symptom Chart" (Symptom No.24).
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
8.CHECK SYMPTOM
Check again. Refer to AT-55, "
Check at Idle".
OK or NG
OK >>INSPECTION END
NG >> GO TO 9.
9.PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-82, "
TCM Input/Output Signal Reference
Va l u e".
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
10.DETECT MALFUNCTIONING ITEM
• Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-60,
"Symptom Chart" (Symptom No.24).
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
A/T Does Not Hold Lock-up ConditionINFOID:0000000003532461
SYMPTOM:
The lock-up condition cannot be maintained for more than 30 seconds.
DIAGNOSTIC PROCEDURE
1.CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT-83, "
CONSULT-II Function (A/T)".
Do the self-diagnostic results indicate torque converter clutch solenoid valve, engine speed signal, turbine rev-
olution sensor, CAN communication?
YES >> Check the malfunctioning system. Refer to AT- 111' AT-109' AT-103' AT- 9 1.
NO >> GO TO 2.
2.CHECK A/T FLUID LEVEL
SCIA5199E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-191
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The lock-up condition cannot be cancelled even after releasing the accelerator pedal.
DIAGNOSTIC PROCEDURE
1.CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT-83, "
CONSULT-II Function (A/T)".
Do the self-diagnostic results indicate torque converter clutch solenoid valve, engine speed signal, turbine rev-
olution sensor, CAN communication?
YES >> Check the malfunctioning system. Refer to AT- 111' AT-109' AT-103' AT- 9 1.
NO >> GO TO 2.
2.CHECK SYMPTOM
Check again. Refer to AT-55, "
Check at Idle".
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3.PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-82, "
TCM Input/Output Signal Reference
Va l u e".
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Engine Speed Does Not Return to IdleINFOID:0000000003532463
SYMPTOM:
When a shift-down is performed, the engine speed does not smoothly return to the idling speed.
DIAGNOSTIC PROCEDURE
1.CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT-13, "
Checking Automatic Trans-
mission Fluid (ATF)".
OK or NG
OK >> GO TO 2.
NG >> Refill ATF.
2.CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT-83, "
CONSULT-II Function (A/T)".
Do the self-diagnostic results indicate front brake solenoid valve, direct clutch solenoid valve, ATF pressure
switch 1, ATF pressure switch 5, accelerator pedal position sensor, vehicle speed sensor A/T (revolution sen-
sor) and vehicle speed sensor MTR?
YES >> Check the malfunctioning system. Refer to AT-134' AT-138, AT-150' AT-154' AT- 11 7, AT-105' AT-
124.
NO >> GO TO 3.
3.CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT-210, "
Control Valve with TCM and A/T Fluid Temperature Sensor 2".
SAT638A

ON-VEHICLE SERVICE
AT-215
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2. Install A/T assembly harness connector to control valve with
TCM.
3. Connect TCM connector.
4. Install new O-ring in A/T assembly harness connector.
NOTE:
• Do not reuse O-ring.
• Apply ATF to O-ring.
5. Install A/T fluid temperature sensor 2 to bracket.
6. Install A/T fluid temperature sensor 2 (with bracket) in control
valve with TCM. Tighten A/T fluid temperature sensor 2 bolts to
the specified torque. Refer to AT-228, "
Component".
CAUTION:
Adjust bolt hole of bracket to bolt hole of control valve with
TCM.
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AT-216
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ON-VEHICLE SERVICE
7. Install control valve with TCM in transmission case.
CAUTION:
• Make sure that turbine revolution sensor securely installs
turbine revolution sensor hole.
• Hang down revolution sensor harness toward outside so
as not to disturb installation of control valve with TCM.
• Adjust A/T assembly harness connector of control valve
with TCM to terminal hole of transmission case.
• Assemble it so that manual valve cutout is engaged with
manual plate projection.
8. Install bolts (A), (B) and (C) in control valve with TCM.
• : Front
9. Tighten bolt (1), (2) and (3) temporarily to prevent dislocation. Then tighten them in order (1 → 2 → 3),
and then tighten other bolts.
• : Front
10. Tighten control valve with TCM bolts to the specified torque.
Refer to AT-228, "
Component".
SCIA5034E
SCIA5142E
Bolt symbol Length mm (in) Number of bolts
A 42 (1.65) 5
B 55 (2.17) 6
C 40 (1.57) 1
SCIA8074E
SCIA8075E

ON-VEHICLE SERVICE
AT-219
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1. Install A/T fluid temperature sensor 2 to bracket.
2. Install A/T fluid temperature sensor 2 (with bracket) in control
valve with TCM. Tighten A/T fluid temperature sensor 2 bolt to
the specified torque. Refer to AT-228, "
Component".
CAUTION:
Adjust bolt hole of bracket to bolt hole of control valve with
TCM.
3. Connect A/T fluid temperature sensor 2 connector (A).
4. Securely fasten A/T fluid temperature sensor 2 harness with ter-
minal clip.
• : Terminal clip
5. Install oil pan to transmission case. Refer to AT-209, "
Oil Pan".
6. Connect the negative battery terminal
7. Refill the A/T with fluid and check fluid level and for fluid leakage. Refer to AT-13, "
Changing Automatic
Transmission Fluid (ATF)".
CAUTION:
After completing installation, check for A/T fluid leakage and fluid level. Refer to AT-13, "
Changing
Automatic Transmission Fluid (ATF)", AT-13, "Checking Automatic Transmission Fluid (ATF)".
Rear Oil SealINFOID:0000000003532479
REMOVAL AND INSTALLATION
Removal
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SCIA8125E

AT-224
< SERVICE INFORMATION >
TRANSMISSION ASSEMBLY
8. Remove crankshaft position sensor (POS) from A/T assembly.
CAUTION:
• Do not subject it to impact by dropping or hitting it.
• Do not disassemble.
• Do not allow metal filings or foreign material to get on the
sensor front edge magnetic area.
• Do not place in an area affected by magnetism.
9. Remove fluid cooler tube.
10. Remove dust cover from converter housing.
11. Turn crankshaft to access and remove the four bolts for drive
plate and torque converter.
CAUTION:
When turning crankshaft, turn it clockwise as viewed from
the front of the engine.
12. Support A/T assembly with a transmission jack.
CAUTION:
When setting the transmission jack, be careful not to allow
it to collide against the drain plug.
13. Remove cross member using power tool.
14. Remove air breather hose. Refer to AT-221, "
Removal and
Installation".
15. Disconnect A/T assembly connector.
16. Remove A/T fluid indicator pipe from A/T assembly.
17. Plug any openings such as the A/T fluid indicator pipe hole.
18. Remove the A/T assembly to engine bolts using power tool.
19. Remove A/T assembly from vehicle using transmission jack.
CAUTION:
• Secure torque converter to prevent it from dropping.
• Secure A/T assembly to a transmission jack.
INSPECTION
Installation and Inspection of Torque Converter
• After inserting a torque converter to a transmission, be sure to
check dimension A to ensure it is within specifications.
INSTALLATION
Installation of the remaining components is in the reverse order of the removal, while paying attention to the
following:
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Dimension A : 24.0 mm (0.94 in) or more
SAT017B