Infiniti FX35 / FX45. Manual - part 49

AT-124

< SERVICE INFORMATION >

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

Description

INFOID:0000000001327209

• The torque converter clutch solenoid valve is activated, with the gear in D

5

, M3, M4 and M5 by the TCM in

response to signals sent from the vehicle speed sensor and accelerator pedal position sensor (throttle posi-
tion sensor). 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 1.0/8) 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-III Reference Value in Data Monitor Mode

INFOID:0000000001327210

On Board Diagnosis Logic

INFOID:0000000001327211

Diagnostic trouble code “P0740 TCC SOLENOID/CIRC” with CONSULT-III or 3rd judgement flicker without
CONSULT-III 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 Cause

INFOID:0000000001327212

• Torque converter clutch solenoid valve
• Harness or connectors

(Solenoid circuit is open or shorted.)

DTC Confirmation Procedure

INFOID:0000000001327213

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.

Turn ignition switch ON.

2.

Select “SELECTION FROM MENU” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III
and check monitor “VHCL/S SE-A/T”, “ACCELE POSI” and “SLCT LVR POSI”.

3.

Touch “START”.

4.

Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL/S SE-A/T: 80 km/h (50 MPH) or more
ACCELE POSI: 0.5/8 - 1.0/8
SLCT LVR POSI: “D” position 
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving
conditions required for this test.

5.

If DTC is detected go to 

AT-124, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III”.

Diagnosis Procedure

INFOID:0000000001327214

1.

CHECK INPUT SIGNAL

 With CONSULT-III

1.

Turn ignition switch ON.

Item name

Condition 

Display value (Approx.) 

TCC SOLENOID

Slip lock-up is active

0.2 - 0.4 A

Lock-up is active

0.4 - 0.6 A

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

AT-125

< SERVICE INFORMATION >

D

E

F

G

H

I

J

K

L

M

A

B

AT

N

O

P

2.

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

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 

AT-160

.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTIONING ITEM

Check 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-215, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform 

AT-124, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

Item name

Condition 

Display value (Approx.)

TCC SOLENOID

Slip lock-up is active

0.2 - 0.4 A

Lock-up is active

0.4 - 0.6 A

AT-126

< SERVICE INFORMATION >

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)

Description

INFOID:0000000001327215

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-III Reference Value in Data Monitor Mode

INFOID:0000000001327216

On Board Diagnosis Logic

INFOID:0000000001327217

Diagnostic trouble code “P0744 A/T TCC S/V FNCTN” with CONSULT-III or 3rd judgement flicker without
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:0000000001327218

• Harness or connectors

(Solenoid circuit is open or shorted.)

• Torque converter clutch solenoid valve
• Hydraulic control circuit

DTC Confirmation Procedure

INFOID:0000000001327219

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.

2.

Select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

3.

Drive vehicle and maintain the following conditions for at least 30 consecutive seconds.
ACCELE POSI: More than 1.0/8
SLCT LVR POSI: “D” position 
TCC SOLENOID: 0.4 - 0.6 A
VEHICLE SPEED: 80 km/h (50 MPH) or more
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-126, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III”.

Diagnosis Procedure

INFOID:0000000001327220

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.

Item name

Condition 

Display value (Approx.)

TCC SOLENOID

Slip lock-up is active

0.2 - 0.4 A

Lock-up is active

0.4 - 0.6 A

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)

AT-127

< SERVICE INFORMATION >

D

E

F

G

H

I

J

K

L

M

A

B

AT

N

O

P

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-160

.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTIONING ITEM

Check 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-215, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

.

NG

>> Repair or replace damaged parts.

4.

CHECK DTC

Perform 

AT-126, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 2.

Item name

Condition 

Display value (Approx.)

TCC SOLENOID

Slip lock-up is active

0.2 - 0.4 A

Lock-up is active

0.4 - 0.6 A