Infiniti F50. Manual - part 59

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE

AT-121

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Operation check

●

Check solenoid valve by listening for its operating sound while
applying battery voltage to the terminal 11 and ground.

SCIA3105E

AT-122

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

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

PFP:31940

Description

ECS0084M

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.

On Board Diagnosis Logic

ECS0084N

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This is an OBD-II self-diagnostic item.

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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 Cause

ECS0084O

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

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Torque converter clutch solenoid valve

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Hydraulic control circuit

DTC Confirmation Procedure

ECS0084P

CAUTION:

Always drive vehicle at a safe speed.

NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch “OFF”
and wait at least 10 seconds before conducting 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)]

–

Check that “GEAR” shows “5”.

–

For shift schedule, refer to 

AT-357, "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-124, "Diagnostic Procedure"

 .

Refer to shift schedule, 

AT-357, "Vehicle Speed When Performing and Releasing Complete Lock-up"

 .

 WITH GST

Follow the procedure “With CONSULT-II”.

SAT014K

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

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Wiring Diagram — AT — TCCSIG

ECS0084Q

TCM terminal and data are reference value. Measured between each terminal and ground.

TCWM0006E

Terminal   

No.

Wire 

color

Item

Condition

Data (Approx.)

20

Y

TCC solenoid 
valve

When   

vehicle 
cruises

When lock-up

More than 2V 

When not lock-up

0V

AT-124

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

Diagnostic Procedure

ECS00A1J

1. 

CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE CIRCUIT

1.

Turn ignition switch to “OFF” position.

2.

Disconnect A/T unit assembly harness connector at the trans-
mission right side.

3.

Check the resistance between terminal and ground.

OK or NG

OK >> GO 

TO 

4.

NG

>> GO TO 2.

2. 

CHECK TERMINAL CORD ASSEMBLY

1.

Remove oil pan. Refer to 

AT-289, "Control Valve Assembly"

 .

2.

Disconnect A/T unit assembly harness connector and control valve assembly harness connector.

3.

Check continuity between A/T unit assembly harness connector
and control valve assembly harness connector.

4.

If OK, check harness for short to ground and short to power.

5.

Reinstall any part removed.

OK or NG

OK

>> GO TO 3.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

3. 

CHECK VALVE RESISTANCE

Check valve resistance

●

Refer to 

AT-125, "Component Inspection"

 .

OK or NG

OK >> GO 

TO 

5.

NG

>> Replace the control valve assembly. Refer to 

AT-289, "Control Valve Assembly"

 .

Solenoid valve

Connector No.

Terminal No. 

(Wire color)

Resistance (Approx.) 

Torque converter clutch 
solenoid valve

F27

8 (Y) - Ground

3 - 9 

Ω

SCIA1830E

Item

Connector No.

Terminal No. (Wire color)

Continuity

A/T unit assembly 
harness connector

F27

8 (R/B)

Yes

Control valve assem-
bly harness connec-
tor

F301

11 (R/B)

SCIA3060E