Infiniti QX56 (JA60). Manual - part 941

TM-66

< COMPONENT DIAGNOSIS >

P0740 TORQUE CONVERTER

3. Start 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 

TM-94, "Diagnosis Procedure"

.

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 

TM-172, "Control Valve with TCM and A/T Fluid

Temperature Sensor 2 and Plug"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform “DTC Confirmation Procedure”.

• Refer to 

TM-65, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

Item name

Condition 

Display value (Approx.)

TCC SOLENOID

When performing slip lock-up.

0.2 - 0.4 A

When performing lock-up.

0.4 - 0.6 A

P0744 TORQUE CONVERTER

TM-67

< COMPONENT DIAGNOSIS >

C

E

F

G

H

I

J

K

L

M

A

B

TM

N

O

P

P0744 TORQUE CONVERTER

Description

INFOID:0000000005148599

This malfunction is detected when the A/T does not lock-up. 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-III Reference Value in Data Monitor Mode

INFOID:0000000005148600

On Board Diagnosis Logic

INFOID:0000000005148601

• This is an OBD-II self-diagnostic item.

• Diagnostic trouble code “P0744 TORQUE CONVERTER” with CONSULT-III 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 Cause

INFOID:0000000005148602

• Harness or connectors

(The solenoid circuit is open or shorted.)

• Torque converter clutch solenoid valve

• Hydraulic control circuit

DTC Confirmation Procedure

INFOID:0000000005148603

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-III

1. Start engine and Select “TCC S/V FNCTN CHECK” of “DTC WORK SUPPORT” mode for “TRANSMIS-

SION” with CONSULT-III 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

SLCT LVR POSI: “D” position 

[Reference speed: Constant speed of more than 80 km/h (50 MPH)]

-

Make sure “GEAR” shows “5”.

-

For shift schedule, refer to 

TM-266, "Vehicle Speed at Which Lock-up Occurs/Releases"

.

-

If “TESTING” does not appear on CONSULT-III 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 

TM-68, "Diagnosis Procedure"

.

Refer to shift schedule, 

TM-266, "Vehicle Speed at Which Lock-up Occurs/Releases"

.

 WITH GST

Follow the procedure “With CONSULT-III”.

Item name

Condition 

Display value (Approx.)

TCC SOLENOID

When performing slip lock-up.

0.2 - 0.4 A

When performing lock-up.

0.4 - 0.6 A

TM-68

< COMPONENT DIAGNOSIS >

P0744 TORQUE CONVERTER

Diagnosis Procedure

INFOID:0000000005148604

1.

CHECK INPUT SIGNAL

With CONSULT-III

1. Turn ignition switch “ON”. 

2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

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 

TM-94, "Diagnosis Procedure"

.

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 

TM-172, "Control Valve with TCM and A/T Fluid

Temperature Sensor 2 and Plug"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform “DTC Confirmation Procedure”.

• Refer to 

TM-67, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

Item name

Condition 

Display value (Approx.)

TCC SOLENOID

When performing slip lock-up.

0.2 - 0.4 A

When performing lock-up.

0.4 - 0.6 A

P0745 PRESSURE CONTROL SOLENOID A

TM-69

< COMPONENT DIAGNOSIS >

C

E

F

G

H

I

J

K

L

M

A

B

TM

N

O

P

P0745 PRESSURE CONTROL SOLENOID A

Description

INFOID:0000000005148605

The line pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in

response to a signal sent from the TCM.

The line pressure duty cycle value is not consistent when the closed throttle position signal is “ON”.

To confirm the line pressure duty cycle at low pressure, the accelerator (throttle) should be open until

the closed throttle position signal is “OFF”.

CONSULT-III Reference Value in Data Monitor Mode

INFOID:0000000005148606

On Board Diagnosis Logic

INFOID:0000000005148607

• This is an OBD-II self-diagnostic item.

• Diagnostic trouble code “P0745 PC SOLENOID A” with CONSULT-III is detected under the following condi-

tions.

- 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 Cause

INFOID:0000000005148608

• Harness or connectors

(The solenoid circuit is open or shorted.)

• Line pressure solenoid valve

DTC Confirmation Procedure

INFOID:0000000005148609

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-III

1. Turn ignition switch “ON” and select “DATA MONITOR” mode for “ENGINE” with CONSULT-III.

2. Engine start and wait at least 5 second.

3.  If DTC is detected, go to 

TM-69, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “With CONSULT-III”.

Diagnosis Procedure

INFOID:0000000005148610

1.

CHECK INPUT SIGNAL

With CONSULT-III

1. Turn ignition switch “ON”.

2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

3. Start the engine.

4. Read out the value of “LINE PRES SOL” while driving.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 2.

Item name

Condition 

Display value (Approx.)

LINE PRES SOL

During driving

0.2 - 0.6 A

Item name

Condition 

Display value (Approx.) 

LINE PRES SOL

During driving

0.2 - 0.6 A