DTC    P0741    Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)

for Preparation Click here


SYSTEM DESCRIPTION

The TCM uses signals from the throttle position sensor, air-flow meter, turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor to help determine the engagement timing of the lock-up clutch. The TCM monitors the engagement of the clutch using the turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor.
Then the TCM compares the engagement condition of the lock-up clutch with the lock-up schedule in the TCM memory to detect shift solenoid valve SL, valve body and torque converter mechanical problems.

DTC No.
DTC Detection Condition
Trouble Area
P0741
When both of the following are detected (2-trip detection logic):
  1. Lock-up does not occur when requested.
  2. Transmission fluid pressure switch No. 3 is ON.
  1. Shift solenoid valve SL remains closed
  2. Valve body is blocked
  3. Torque converter assembly
  4. Automatic transaxle (clutch, brake or gear etc.)
  5. Line pressure is too low

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the TCM based on the speed sensor (NT), speed sensor (NC), engine speed, engine load, engine temperature, vehicle speed, transmission fluid temperature, and gear selection. The TCM determines the lock-up status of the torque converter by comparing the engine speed (NE) to the input turbine rpm (NT). The TCM calculates the actual transmission gear by comparing the input turbine rpm (NT) to the counter gear rpm (NC). When conditions are appropriate, the TCM requests "lock-up" by applying control voltage to shift solenoid SL. When SL is turned on, it applies pressure to the lock-up relay valve and locks the torque converter.
If the TCM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the TCM interprets this as a fault in shift solenoid valve SL or lock-up system performance. The TCM will turn on the MIL and store the DTC.

HINT:
Example:
When any of the following is met, the system judges it as a malfunction.
  1. There is a difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up.
    (Engine speed is at least 70 rpm greater than the input turbine speed.)

INSPECTION PROCEDURE

HINT:
Using the intelligent tester 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.

PERFORM ACTIVE TEST

  1. Warm up the engine.

  2. Turn the engine switch off.

  3. Connect the intelligent tester to the DLC3.

  4. Turn the engine switch on (IG).

  5. Turn the intelligent tester on.

  6. Enter the following menus: Powertrain / ECT / Active Test.

  7. According to the display on the intelligent tester, perform the Active Test.

    Tester Display
    		Test Part
    		Control Range
    		Diagnostic Note
    Activate the Lock Up
    		Controls the shift solenoid SLU and SL to set the automatic transaxle to the lock-up condition.
    		ON/OFF
    		Can be used to check SLU and SL solenoid operation.
    [Vehicle Condition]
    1. Throttle valve opening angle: Less than 20%
    2. Vehicle speed:60 km/h (37 mph) or more, and 6th gear

    HINT:
    1. This test can be conducted when the vehicle speed is 60 km/h (37 mph) or more.


  8. Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.

    HINT:
    1. When changing the accelerator pedal opening angle while driving, if the engine speed does not change, lock-up is on.
    2. 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.)

    G029214E29

1.CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0741)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Turn the intelligent tester on.

  1. Enter the following menus: Powertrain / ECT / DTC.

  1. Read the DTCs using the intelligent tester.

    Result:

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

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


B
GO TO DTC CHART (Click here)
A


2.CHECK TRANSMISSION WIRE


    C133212E51

  1. Remove the TCM from the transaxle.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    6 (SL) - Body ground
    		20°C (68°F)
    		11 to 15 Ω
    Text in Illustration 
    *a
    		Component without harness connected
    (Transmission Wire)


NG
Go to step 6
OK


3.INSPECT SHIFT SOLENOID VALVE SL (OPERATION)


    C133218E02

  1. Remove shift solenoid valve SL.

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

    OK:
    Valve moves and makes an operating sound.
    Text in Illustration 
    *1
    		Shift Solenoid Valve SL


NG
REPLACE SHIFT SOLENOID VALVE SL (Click here)
OK


4.INSPECT TRANSMISSION VALVE BODY ASSEMBLY

  1. Check the transmission valve body assembly (Click here).

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


NG
REPLACE TRANSMISSION VALVE BODY ASSEMBLY (Click here)
OK


5.INSPECT TORQUE CONVERTER ASSEMBLY

  1. Check the torque converter assembly (Click here).

OK:
The torque converter operates normally.


NG
REPLACE TORQUE CONVERTER ASSEMBLY (Click here)
OK

REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY (Click here)  

6.INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)


    C133217E02

  1. Remove shift solenoid valve SL.

  1. 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
    Text in Illustration 
    *1
    		Shift Solenoid Valve SL


NG
REPLACE SHIFT SOLENOID VALVE SL (Click here)
OK

REPLACE TRANSMISSION WIRE (Click here)