2004 INFINITI QX56 lock

TROUBLE DIAGNOSIS
AT-91
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Revision: August 20072004 QX56
CONSULT-II Function (A/T)UCS002D8
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II REFERENCE VALUE
NOTICE:
1. The CONSULT-II electrically displays shift timing and lock-up timing (that is, operation timing of each sole-
noid).
Check for time difference between actual shift timing and the CONSULT-II display. If the difference is
noticeable, mechanical parts (except solenoids, sensors, etc.) may be malfunctioning. Check mechanical
parts using applicable diagnostic procedures.
2. Shift schedule (which implies gear position) displayed on CONSULT-II and that indicated in Service Man-
ual may differ slightly. This occurs because of the following reasons:
–Actual shift schedule has more or less tolerance or allowance,
–Shift schedule indicated in Service Manual refers to the point where shifts start, and
–Gear position displayed on CONSULT-II indicates the point where shifts are completed.
3. Display of solenoid valves on CONSULT-II changes at the start of shifting, while gear position is displayed
upon completion of shifting (which is computed by TCM).
TCM diagnostic mode Description
WORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the TCM for setting the status
suitable for required operation, input/output signals are received from the TCM and received data is
displayed.
SELF-DIAG RESULTS Displays TCM self-diagnosis results.
DATA MONITOR Displays TCM input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
FUNCTION TESTConducted by CONSULT-II instead of a technician to determine whether each system is “OK” or
“NG”.
ECU PART NUMBER TCM part number can be read.
Item name Condition Display value
AT F T E M P S E 1
0°C (32° F) - 20°C (68°F) - 80°C (176°F)3.2 - 2.5 - 0.8 V
AT F T E M P S E 23.2 - 2.4 - 0.65 V
TCC SOLENOIDWhen perform slip lock-up 0.2 - 0.4 A
When perform lock-up 0.4 - 0.6 A
SLCT LVR POSISelector lever in “N”,“P” position. N/P
Selector lever in “R” position. R
Selector lever in “D” position. D
Selector lever in “4” position. 4
Selector lever in “3” position. 3
Selector lever in “2” position. 2
Selector lever in “1” position. 1
VHCL/S SE·A/T During driving Approximately matches the
speedometer reading.
ENGINE SPEED Engine running Closely matches the tachometer
reading.
LINE PRES SOL During driving 0.2 - 0.6 A
TURBINE REV During driving (lock-up ON) Approximately matches the
engine speed.
VHCL/S SE·MTR During driving Approximately matches the
speedometer reading.

AT-94
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Display Items List
X: Applicable, —: Not applicable
Items (CONSULT-II
screen terms)Malfunction is detected when...TCM self-
diagnosisOBD-II (DTC)
“A/T” with
CONSULT-IIMIL indicator
lamp*1,
“ENGINE” with
CONSULT-II or
GST
CAN COMM CIRCUIT

When a malfunction is detected in CAN communications U1000 U1000
STARTER RELAY/
CIRC

If this signal is ON other than in P or N position, this is judged to be a
malfunction.
(And if it is OFF in P or N position, this too is judged to be a malfunc-
tion.)P0615 —
TCM

TCM is malfunctioning. P0700 P0700
PNP SW/CIRC

PNP switch 1-4 signals input with impossible pattern

PNP switch 3 monitor terminal cut line

“P” position is detected from N position without any other position
being detected in between.P0705 P0705
VEH SPD SEN/CIR AT
(Revolution sensor)

Signal from vehicle speed sensor A/T (Revolution sensor) not input
due to cut line or the like

Unexpected signal input during running

After ignition switch is turned ON, unexpected signal input from vehicle
speed sensor MTR before the vehicle starts movingP0720 P0720
ENGINE SPEED SIG

TCM does not receive the CAN communication signal from the ECM. P0725 —
TCC SOLENOID/CIRC

Normal voltage not applied to solenoid due to cut line, short, or the like P0740 P0740
A/T TCC S/V FNCTN

A/T cannot perform lock-up even if electrical circuit is good.

TCM detects as irregular by comparing difference value with slip rota-
tion.P0744 P0744*2
L/PRESS SOL/CIRC

Normal voltage not applied to solenoid due to cut line, short, or the like

TCM detects as irregular by comparing target value with monitor value.P0745 P0745
TCM·RAM

TCM memory (RAM) is malfunctioning. P1702 —
TCM·ROM

TCM memory (ROM) is malfunctioning. P1703 —
TP SEN/CIRC A/T

TCM does not receive the proper accelerator pedal position signals
(input by CAN communication) from ECM.P1705 P1705
ATF TEMP SEN/CIRC

During running, the ATF temperature sensor signal voltage is exces-
sively high or lowP1710 P0710
TURBINE REV S/CIRC

TCM does not receive the proper voltage signal from the sensor.

TCM detects an irregularity only at position of 4th gear for turbine revo-
lution sensor 2.P1716 P1716
VEH SPD SE/CIR·MTR

Signal (CAN communication) from vehicle speed sensor MTR not input
due to cut line or the like

Unexpected signal input during runningP1721 —
A/T INTERLOCK

Except during shift change, the gear position and ATF pressure switch
states are monitored and comparative judgement made.P1730 P1730
A/T 1ST E/BRAKING

Each ATF pressure switch and solenoid current is monitored and if a
pattern is detected having engine braking 1st gear other than in the M1
position, a malfunction is detected.P1731 —
I/C SOLENOID/CIRC

Normal voltage not applied to solenoid due to functional malfunction,
cut line, short, or the like

TCM detects as irregular by comparing target value with monitor value.P1752 P1752

AT-102
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
7. Perform test drive to check gear shift feeling in accordance with
instructions displayed.
8. Touch “YES” or “NO”.
9. CONSULT-II procedure is ended.

If “NG” appears on the screen, a malfunction may exist.
Go to “Diagnostic Procedure”.
Display Items List
*: Do not use, but displayed.
SCIA5163E
SCIA5162E
DTC work support item Description Check item
I/C SOL FUNCTN CHECK* — —
FR/B SOL FUNCTN CHECK* — —
D/C SOL FUNCTN CHECK* — —
HLR/C SOL FUNCTN CHECK* — —
LC/B SOL FUNCTN CHECK* — —
TCC SOL FUNCTN CHECKFollowing items for “TCC solenoid function (lock-up) ” can be con-
firmed.

Self-diagnosis status (whether the diagnosis is being conducted
or not)

Self-diagnosis result (OK or NG)

TCC solenoid valve

Hydraulic control circuit

AT-112
DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)
Revision: August 20072004 QX56
DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)PFP:32702
DescriptionUCS002DV
The revolution sensor detects the revolution of the idler gear parking pawl lock gear and emits a pulse signal.
The pulse signal is sent to the TCM which converts it into vehicle speed.
CONSULT-II Reference ValueUCS002DW
On Board Diagnosis LogicUCS002DX

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “VEH SPD SEN/CIR AT” with CONSULT-II or P0720 without CONSULT-II is
detected under the following conditions.
–When TCM does not receive the proper voltage signal from the sensor.
–After ignition switch is turned “ON”, irregular signal input from vehicle speed sensor MTR before the vehi-
cle starts moving.
Possible CauseUCS002DY

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

Revolution sensor

Vehicle speed sensor MTR
DTC Confirmation ProcedureUCS002DZ
CAUTION:

Always drive vehicle at a safe speed.

Be careful not to rev engine into the red zone on the tachometer.
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. Drive vehicle and check for an increase of “VHCL/S SE·A/T”
value in response to “VHCL/S SE·MTR” value.
If the check result is NG, go to AT-113, "
Diagnostic Procedure" .
If the check result is OK, go to following step.
4. Select “DATA MONITOR” mode for “ENGINE” with CONSULT-II.
5. Start engine and maintain the following conditions for at least 5
consecutive seconds.
VHCL SPEED SE: 30 km/h (19 MPH) or more
THRTL POS SEN: More than 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.
If the check result is NG, go to AT-113, "
Diagnostic Procedure" .
If the check result is OK, go to following step.
6. Maintain the following conditions for at least 5 consecutive seconds.
ENGINE SPEED: 3,500 rpm or more
THRTL POS SEN: More than 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.
If the check result is NG, go to AT-113, "
Diagnostic Procedure" .
Item name Condition Display value (km/h)
VHCL/S SE·A/T During driving Approximately matches the speedometer reading.
BCIA0030E

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

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

AT-122
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
Revision: August 20072004 QX56
WITH GST
Follow the procedure “With CONSULT-II”.
Diagnostic ProcedureUCS002EI
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- 9 0 , "
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-121, "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-241, "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