2007 INFINITI QX56 lock

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

AT-114
< SERVICE INFORMATION >
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
Refer to shift schedule, AT-299, "Vehicle Speed When Performing and Releasing Complete Lock-up".
WITH GST
Follow the procedure “With CONSULT-II”.
Diagnosis ProcedureINFOID:0000000003532315
1.CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T”
with CONSULT-II.
3. Start the engine.
4. Read out the value of “TCC SOLENOID” while driving.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT-158
.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.DETECT MALFUNCTIONING ITEM
Check the following items:
• The A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-210, "Control Valve with TCM and A/T Fluid Tem-
perature Sensor 2".
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to AT-113, "
DTC Confirmation Procedure".
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
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
SCIA4793E

AT-126
< SERVICE INFORMATION >
DTC P1730 A/T INTERLOCK
DTC P1730 A/T INTERLOCK
DescriptionINFOID:0000000003532342
• Fail-safe function to detect interlock conditions.
On Board Diagnosis LogicINFOID:0000000003532343
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1730 A/T INTERLOCK” with CONSULT-II is detected when TCM does not receive
the proper voltage signal from the sensor and switch.
• TCM monitors and compares gear position and conditions of each ATF pressure switch when gear is steady.
Possible CauseINFOID:0000000003532344
• Harness or connectors
(The solenoid and switch circuit is open or shorted.)
• Low coast brake solenoid valve
• ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000003532345
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. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “A/T” with CONSULT-II.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 2
consecutive seconds.
Selector lever: “D” position
5. If DTC is detected, go to AT-127, "
Diagnosis Procedure".
WITH GST
Follow the procedure “With CONSULT-II”.
Judgement of A/T InterlockINFOID:0000000003532346
When A/T Interlock is judged to be malfunctioning, the vehicle should be fixed in 2nd gear, and should be set
in a condition in which it can travel.
When one of the following fastening patterns is detected, the fail-safe function in correspondence with the indi-
vidual pattern should be performed.
A/T INTERLOCK COUPLING PATTERN TABLE
BCIA0031E

DTC P1730 A/T INTERLOCK
AT-127
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l: NG, X: OK
Diagnosis ProcedureINFOID:0000000003532347
1.SELF-DIAGNOSIS
With CONSULT-II
1. Drive vehicle.
2. Stop vehicle and turn ignition switch “OFF”.
3. Turn ignition switch “ON”.
4. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
OK or NG
OK >> GO TO 2.
NG >> Check low coast brake solenoid valve circuit and func-
tion. Refer to AT-146
, AT-148.
2.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to AT-126, "
DTC Confirmation Procedure".
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3.CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT-158
.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4.DETECT MALFUNCTIONING ITEM
Check the following items:
• The A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-210, "Control Valve with TCM and A/T Fluid Tem-
perature Sensor 2".
NG >> Repair or replace damaged parts.
Gear positionATF pressure switch output
Fail-safe
functionClutch pressure output pattern after fail-safe func-
tion
SW3
(I/C)SW6
(HLR/
C)SW5
(D/C)SW1
(FR/B)SW2
(LC/B)I/C HLR/C D/C FR/B LC/B L/U
A/T interlock
coupling pat-
tern3rd – X X –lHeld in
2nd gearOFF OFF ON OFF OFF OFF
4th – X X –lHeld in
2nd gearOFF OFF ON OFF OFF OFF
5th X X – XlHeld in
2nd gearOFF OFF ON OFF OFF OFF
BCIA0031E

MAIN POWER SUPPLY AND GROUND CIRCUIT
AT-159
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Diagnosis ProcedureINFOID:0000000003532439
1.CHECK TCM POWER SOURCE STEP 1
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector.
3. Check voltage between A/T assembly harness connector termi-
nals and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.CHECK TCM POWER SOURCE STEP 2
1. Disconnect A/T assembly harness connector.
2. Turn ignition switch ON. (Do not start engine.)
3. Check voltage between A/T assembly harness connector termi-
nals and ground.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING ITEM
Check the following items:
• Harness for short or open between battery and A/T assembly harness connector terminals 1, 2
• Harness for short or open between ignition switch and A/T assembly harness connector terminal 6
• 10A fuse [No. 3, located in the fuse block (J/B)] and 10A fuse (No. 49, located in the IPDM E/R)
• Ignition switch, Refer to PG-3
.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4.CHECK TCM GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector.
3. Check continuity between A/T assembly harness connector F9
terminals 5, 10 and ground.
If OK, check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
5.DETECT MALFUNCTIONING ITEM
Item Connector Terminal Voltage
TCM F91 - Ground
Battery voltage
2 - Ground
6 - Ground 0V
SCIA2104E
Item Connector Terminal Voltage
TCM F91 - Ground
Battery voltage 2 - Ground
6 - Ground
SCIA2105E
Continuity should exist.
SCIA2106E

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

AT-190
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYMPTOMS
Check A/T fluid level. Refer to AT-13, "Checking Automatic Trans-
mission Fluid (ATF)".
OK or NG
OK >> GO TO 3.
NG >> Refill ATF.
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".
2. Check A/T fluid condition. Refer to AT-51, "
Inspections Before
Trouble Diagnosis".
OK or NG
OK >> GO TO 4.
NG >> GO TO 7.
4.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.25).
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5.CHECK SYMPTOM
Check again. Refer to AT-55, "
Check at Idle".
OK or NG
OK >>INSPECTION END
NG >> GO TO 6.
6.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.
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.25).
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
Lock-up Is Not ReleasedINFOID:0000000003532462
SYMPTOM:
SAT638A
SCIA5199E