P0741

DTC Code	DTC Name
P0741	Torque Converter Clutch Circuit Performance or Stuck OFF

SYSTEM DESCRIPTION

The ECM uses signals from the throttle position sensor, air-flow meter, input speed sensor NT, output speed sensor NC and crankshaft position sensor to help determine the engagement timing of the lock-up clutch. The ECM monitors the engagement of the clutch using the input speed sensor NT, output speed sensor NC and crankshaft position sensor.

Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect mechanical malfunctions of the solenoid (SL) valve, transmission valve body assembly and torque converter assembly.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0741	Torque Converter Clutch Circuit Performance or Stuck OFF	All of the following conditions are met (2-trip detection logic): The engine coolant temperature is 40°C (104°F) or higher. The ATF temperature is -10°C (14°F) or higher. The vehicle is being driven with the shift lever in D. No malfunctions are detected in the solenoid (SL1, SL2, SL3, SL4, SL and SLU) valves, transmission revolution sensors (NT and NC), coolant temperature sensor, oil temperature sensor, knock sensor, electronic throttle or CAN communication system. During lock-up request, the engine speed and turbine speed slip amount is 70 rpm or more.	Solenoid (SL) valve remains closed Transmission valve body assembly is blocked Torque converter assembly Automatic transaxle assembly (clutch, brake, gear, etc.) Line pressure is too low	Comes on	DTC stored

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0741

Torque Converter Clutch Circuit Performance or Stuck OFF

All of the following conditions are met (2-trip detection logic):

The engine coolant temperature is 40°C (104°F) or higher.
The ATF temperature is -10°C (14°F) or higher.
The vehicle is being driven with the shift lever in D.
No malfunctions are detected in the solenoid (SL1, SL2, SL3, SL4, SL and SLU) valves, transmission revolution sensors (NT and NC), coolant temperature sensor, oil temperature sensor, knock sensor, electronic throttle or CAN communication system.
During lock-up request, the engine speed and turbine speed slip amount is 70 rpm or more.

Solenoid (SL) valve remains closed
Transmission valve body assembly is blocked
Torque converter assembly
Automatic transaxle assembly (clutch, brake, gear, etc.)
Line pressure is too low

Comes on

DTC stored

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the ECM based on the input speed sensor NT, output speed sensor NC, engine speed, engine load, engine temperature, vehicle speed, automatic transaxle fluid temperature and gear selection signals. The ECM determines the lock-up status of the torque converter by comparing the engine speed (NE) signal to the input speed sensor NT signal. The ECM calculates the actual transmission gear by comparing the input speed sensor NT signal to the output speed sensor NC signal. When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to the solenoid (SL) valve. When the solenoid (SL) valve is turned on, it applies pressure to the lock-up relay valve and locks the torque converter.

If the ECM does not detect lock-up after lock-up has been requested or if it detects lock-up when it is not requested, it interprets this as a malfunction of the solenoid (SL) valve or in lock-up system performance, illuminates the MIL and stores this DTC.

Tech Tips

Example:

If the following conditions are met, the system judges it as a malfunction.

There is a difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter assembly when the ECM commands lock-up.

(Engine speed is at least 70 rpm greater than the input turbine speed.)

CONFIRMATION DRIVING PATTERN

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Tech Tips

After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off and wait for 2 minutes or more.
Turn the ignition switch to ON and turn the GTS on.
Start the engine.
Perform the Lock-up Function inspection in Road Test.

Click here
Stop the vehicle.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0741.

Check the DTC judgment result.

GTS Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

Tech Tips

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, perform the Confirmation Driving Pattern and check the DTC judgment result again.

WIRING DIAGRAM

Refer to the wiring diagram for DTC P2769.

Click here

CAUTION / NOTICE / HINT

Note

Perform registration and/or initialization when parts related to the automatic transaxle are replaced.

Click here

Tech Tips

Using the GTS to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

ACTIVE TEST

Warm up the engine.
Turn the ignition switch off.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the Lock Up.

Perform the Active Test according to the display on the GTS.

Powertrain > Engine and ECT > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Activate the Lock Up	Operates the solenoid (SLU and SL) valves to control the automatic transaxle lock-up condition	ON/OFF	Can be used to check the operation of the solenoid (SLU and SL) valves. [Vehicle Condition] Throttle valve opening angle: Less than 20% Vehicle speed: 60 km/h (37 mph) or more in 6th gear

Tester Display

Measurement Item

Control Range

Diagnostic Note

Activate the Lock Up

Operates the solenoid (SLU and SL) valves to control the automatic transaxle lock-up condition

ON/OFF

Can be used to check the operation of the solenoid (SLU and SL) valves.

[Vehicle Condition]

Throttle valve opening angle: Less than 20%
Vehicle speed: 60 km/h (37 mph) or more in 6th gear

Powertrain > Engine and ECT > Active Test

Tester Display
Activate the Lock Up

Tech Tips

This Active Test can be performed when the vehicle speed is 60 km/h (37 mph) or more.

Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
Tech Tips
- When changing the accelerator pedal opening angle while driving, if the engine speed does not change, lock-up is on.
- Slowly release, but not fully, the accelerator pedal in order to decelerate. (Fully releasing the pedal will close the throttle valve and lock-up may be turned off.)

PROCEDURE

CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0741)

Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Powertrain > Engine and ECT > Trouble Codes

Read the DTCs using the GTS.

Result

Result	Proceed to
Only DTC P0741 is output	A
DTC P0741 and other DTCs are output	B

Tech Tips

If any DTCs other than DTC P0741 are output, perform the troubleshooting for those DTCs first.
If a solenoid valve is stuck ON or OFF, DTCs for several solenoid valves including the malfunctioning solenoid valve will be stored.

B

GO TO DTC CHART Click here

A

CHECK TRANSMISSION WIRE

*a
Component without harness connected

(Transmission Wire)

Remove the wiring harness connector.

Click here

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
A-6 (SL) - Body ground	20°C (68°F)	11 to 15 Ω

Result

Proceed to
OK
NG

NG

INSPECT SOLENOID (SL) VALVE (RESISTANCE) Click here

OK

INSPECT SOLENOID (SL) VALVE (OPERATION)

*1 Solenoid (SL) Valve

Remove the solenoid (SL) valve.

Click here

Connect a positive (+) lead from the battery to the terminal of the solenoid valve connector and a negative (-) lead to the solenoid body. Check that the valve moves and makes an operating sound.

OK
Valve moves and makes an operating sound.

Result

Proceed to
OK
NG

NG

REPLACE SOLENOID (SL) VALVE Click here

OK

INSPECT TRANSMISSION VALVE BODY ASSEMBLY

Check the transmission valve body assembly.

Click here

OK
There is no foreign matter on each valve and they operate smoothly.

Result

Proceed to
OK
NG

NG

REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

OK

INSPECT TORQUE CONVERTER ASSEMBLY

Check the torque converter assembly.

Click here

OK
The torque converter assembly is normal.

Result

Proceed to
OK
NG

OK

REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Click here

NG

REPLACE TORQUE CONVERTER ASSEMBLY Click here

INSPECT SOLENOID (SL) VALVE (RESISTANCE)

*1 Solenoid (SL) Valve

Remove the solenoid (SL) valve.

Click here

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
Solenoid Connector (SL) - Solenoid Body (SL)	20°C (68°F)	11 to 15 Ω

Result

Proceed to
OK
NG

OK

REPLACE TRANSMISSION WIRE Click here

NG

REPLACE SOLENOID (SL) VALVE Click here

AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0741