AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0741

DTC Code	DTC Name
P0741	Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve DSL)

SYSTEM DESCRIPTION

The ECM uses the signals from the throttle position sensor, air-flow meter, turbine (input) speed sensor, intermediate (counter) shaft speed sensor and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.

Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect a mechanical problems of the shift solenoid valve DSL, valve body and torque converter clutch.

DTC No.	DTC Detection Condition	Trouble Area
P0741	Lock-up does not occur when driving in lock-up range Lock-up remains ON in lock-up OFF range (2-trip detection logic)	Shift solenoid valve DSL remains open or closed Valve body is blocked Torque converter clutch Automatic transaxle (clutch, brake or gear etc.) Line pressure is too low

DTC No.

DTC Detection Condition

Trouble Area

P0741

Lock-up does not occur when driving in lock-up range

Lock-up remains ON in lock-up OFF range (2-trip detection logic)

Shift solenoid valve DSL remains open or closed
Valve body is blocked
Torque converter clutch
Automatic transaxle (clutch, brake or gear etc.)
Line pressure is too low

MONITOR DESCRIPTION

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

If the ECM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the ECM interprets this as a fault in the shift solenoid valve DSL or lock-up system performance. The ECM will turn on the MIL and store the DTC.

Tech Tips

Example:

When any of the following is met, the system judges it as a malfunction.

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

(Engine speed is at least 100 rpm greater than input turbine speed.)
There is no difference in rotation between the input side (engine speed) and output side (input turbine speed) of the torque converter when the ECM commands lock-up off.

(The difference between engine speed and input turbine speed is less than 35 rpm.)

INSPECTION PROCEDURE

Tech Tips

Using the Intelligent tester to perform Active Test 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 Test early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Test.

PERFORM ACTIVE TEST

Warm up the engine.
Turn the engine switch off.
Connect the Intelligent tester to the DLC3.
Turn the engine switch on (IG).
Select the item "Enter / Powertrain / Engine and ECT / Active Test".

According to the display on the tester, perform the "Active Test".

Tester Display	Test Part	Control Range	Diagnostic Note
Activate the Lock Up	[Test Details] Control the shift solenoid DSL to set the automatic transaxle to the lock-up condition. [Vehicle Condition] Throttle valve opening angle: Less than 35 % Vehicle Speed: 58 km/h (36 mph) or more	ON/OFF	Possible to check the DSL operation.

Tester Display

Test Part

Control Range

Diagnostic Note

Activate the Lock Up

[Test Details]

Control the shift solenoid DSL to set the automatic transaxle to the lock-up condition.

[Vehicle Condition]

Throttle valve opening angle: Less than 35 %

Vehicle Speed: 58 km/h (36 mph) or more

ON/OFF

Possible to check the DSL operation.

Tech Tips

This test can be conducted when the vehicle speed is 60 km/h (37 mph) or more.
This test can be conducted in the 4th gear.

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 Intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the Intelligent tester main switch on.
Select the item "Enter / Powertrain / Engine and ECT / Trouble Codes".

Read the DTCs using the Intelligent tester.

Result

Display (DTC output)	Proceed to
Only "P0741" is output	A
"P0741" and other DTCs	B

Tech Tips

If any other codes besides "P0741" are output, perform the troubleshooting for those DTCs first.

GO TO DTC CHART

INSPECT TRANSMISSION WIRE (DSL)

Disconnect the transmission wire connector from the transaxle.

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

Standard resistance

Tester Connection	Condition	Specified Condition
3 - Body ground	20°C (68°F)	11 to 13 Ω

INSPECT SHIFT SOLENOID VALVE (DSL) Click here

CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

Connect the transmission wire connector.
Disconnect the ECM connector.

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

Standard resistance

Tester Connection	Condition	Specified Condition
D41-79 (DSL) - Body ground	20°C (68°F)	11 to 13 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT SHIFT SOLENOID VALVE (DSL)

Remove the shift solenoid valve DSL.

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

Standard resistance

Tester Connection	Condition	Specified Condition
Solenoid Connector (DSL) - Solenoid Body (DSL)	20°C (68°F)	11 to 13 Ω

Connect the positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.

OK

The solenoid valve makes an operating sound.

OK
The solenoid valve makes an operating sound.

REPLACE SHIFT SOLENOID VALVE (DSL) Click here

CHECK TRANSMISSION WIRE

OK

The connectors and pins are securely installed.

There is no open or short on the wire harness.

NG
REPAIR OR REPLACE TRANSMISSION WIRE Click here

OK
INSPECT TRANSMISSION VALVE BODY ASSEMBLY

OK

There are no foreign objects on each valve and they operate smoothly.

NG
REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

OK
INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY

OK

The torque converter clutch operates normally.

NG
REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY

OK

REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Click here

OK
The connectors and pins are securely installed.
There is no open or short on the wire harness.