2004 INFINITI QX56 torque

TROUBLE DIAGNOSIS
AT-97
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Revision: August 20072004 QX56
DATA MONITOR MODE
Operation Procedure
1. Perform “CONSULT-II SETTING PROCEDURE” Refer to AT-93, "CONSULT-II SETTING PROCEDURE"
.
2. Touch “DATA MONITOR”.
NOTE:
When malfunction is detected, CONSULT-II performs
“REAL-TIME DIAGNOSIS”. Also, any malfunction detected
while in this mode will be displayed at real time.
Display Items List
X: Standard, —: Not applicable
BCIA0031E
Monitored item (Unit)Monitor Item Selection
Remarks ECU
INPUT
SIGNALSMAIN SIG-
NALSSELEC-
TION
FROM
MENU
VHCL/S SE·A/T (km/h) X X X Revolution sensor
VHCL/S SE·MTR (km/h) X — X
ACCELE POSI (0.0/8) X — X Accelerator pedal position signal
THROTTLE POSI (0.0/8) X X XDegree of opening for accelerator recognized by
the TCM
For fail-safe operation, the specific value used
for control is displayed.
CLSD THL POS (ON-OFF display) X — X
Signal input with CAN communications
W/O THL POS (ON-OFF display) X — X
BRAKE SW (ON-OFF display) X — X Stop lamp switch
GEAR — X XGear position recognized by the TCM updated
after gear-shifting
ENGINE SPEED (rpm) X X X
TURBINE REV (rpm) X X X
OUTPUT REV (rpm) X X X
GEAR RATIO — X X
TC SLIP SPEED (rpm) — X XDifference between engine speed and torque
converter input shaft speed
F SUN GR REV (rpm) — — X
F CARR GR REV (rpm) — — X
AT F T E M P S E 1 ( V ) X — X
AT F T E M P S E 2 ( V ) X — X
AT F T E M P 1 (°C) — X X
AT F T E M P 2 (°C) — X X
BATTERY VOLT (V) X — X
ATF PRES SW 1 (ON-OFF display) X X X (for FR/B solenoid)
ATF PRES SW 2 (ON-OFF display) X X X (for LC/B solenoid)
ATF PRES SW 3 (ON-OFF display) X X X (for I/C solenoid)

AT-118
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
Revision: August 20072004 QX56
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVEPFP:31940
DescriptionUCS002E7

The torque converter clutch solenoid valve is activated, with the gear in D4 , D5 by the TCM in response
to signals sent from the vehicle speed sensor and accelerator pedal position sensor (throttle position sen-
sor). Torque converter clutch piston operation will then be controlled.

Lock-up operation, however, is prohibited when A/T fluid temperature is too low.

When the accelerator pedal is depressed (less than 1/8) in lock-up condition, the engine speed should not
change abruptly. If there is a big jump in engine speed, there is no lock-up.
CONSULT-II Reference ValueUCS002E8
On Board Diagnosis LogicUCS002E9

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “TCC SOLENOID/CIRC” with CONSULT-II or P0740 without CONSULT-II is
detected under the following conditions.
–When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
–When TCM detects as irregular by comparing target value with monitor value.
Possible CauseUCS002EA

Torque converter clutch solenoid valve

Harness or connectors
(The solenoid circuit is open or shorted.)
DTC Confirmation ProcedureUCS002EB
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. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “ENGINE” with CONSULT-II.
3. Start engine and maintain the following conditions for at least 5
consecutive seconds.
VHCL SPEED SE: 80 km/h (50 MPH) or more
ACCELE POS: 0.5/8 - 1.0/8
SELECTOR LEVER: “D” position
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
4. If DTC is detected go to AT-119, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.) (A)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4
When performing lock-up 0.4 - 0.6
BCIA0030E

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
AT-119
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Revision: August 20072004 QX56
Diagnostic ProcedureUCS002EC
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
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 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT- 11 8 , "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT - 2 4 1 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
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-120
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
Revision: August 20072004 QX56
6. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-118, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
AT-121
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Revision: August 20072004 QX56
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)PFP:31940
DescriptionUCS002ED
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 ValueUCS002EE
On Board Diagnosis LogicUCS002EF

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “A/T TCC S/V FNCTN” with CONSULT-II or P0744 without CONSULT-II is
detected under the following conditions.
–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 CauseUCS002EG

Harness or connectors
(The solenoid circuit is open or shorted.)

Torque converter clutch solenoid valve

Hydraulic control circuit
DTC Confirmation ProcedureUCS002EH
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- 6 7 , "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- 1 2 2 , "
Diagnostic Procedure" .
Refer to shift schedule, AT-67, "
Vehicle Speed When Performing and Releasing Complete Lock-up" .
Item name Condition Display value (Approx.) (A)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4
When performing lock-up 0.4 - 0.6
BCIA0030E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-215
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Revision: August 20072004 QX56
10. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
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-68,
"Symptom Chart" (Symptom No.13).
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
A/T Does Not Perform Lock-upUCS002IU
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- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
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- 11 8 , "DTC P0740 TORQUE CONVERTER
CLUTCH SOLENOID VALVE" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" , AT- 1 3 4 , "DTC
P1716 TURBINE REVOLUTION SENSOR" , AT- 1 2 9 , "DTC P1705 THROTTLE POSITION SEN-
SOR" , AT-103, "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT- 1 3 , "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 3.
NG >> Refill ATF.
SAT6 3 8A

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-217
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Revision: August 20072004 QX56
7. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"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- 6 3 , "
Cruise Test - Part 1" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 9.
9. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
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-68,
"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 ConditionUCS002IV
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- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
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- 11 8 , "DTC P0740 TORQUE CONVERTER
CLUTCH SOLENOID VALVE" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" , AT- 1 3 4 , "DTC
P1716 TURBINE REVOLUTION SENSOR" , AT-103, "DTC U1000 CAN COMMUNICATION
LINE" .
NO >> GO TO 2.

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-219
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Revision: August 20072004 QX56
7. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"Symptom Chart" (Symptom No.25).
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
Lock-up Is Not ReleasedUCS002IW
SYMPTOM:
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- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
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- 11 8 , "DTC P0740 TORQUE CONVERTER
CLUTCH SOLENOID VALVE" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" , AT- 1 3 4 , "DTC
P1716 TURBINE REVOLUTION SENSOR" , AT-103, "DTC U1000 CAN COMMUNICATION
LINE" .
NO >> GO TO 2.
2. CHECK SYMPTOM
Check again. Refer to AT- 6 3 , "
Cruise Test - Part 1" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
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.