AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0741

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

SYSTEM DESCRIPTION

The ECM 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 ECM monitors the engagement of the clutch using the turbine (input) speed sensor, intermediate (counter gear) speed sensor 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 shift solenoid valve SL, valve body and torque converter mechanical problems.

DTC No. DTC Detection Condition Trouble Area
P0741 Lock-up does not occur when requested. (2-trip detection logic):

  • Shift solenoid valve SL remains closed

  • Valve body is blocked

  • Torque converter assembly

  • 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 speed, engine load, engine temperature, vehicle speed, transmission fluid temperature, and gear selection. The ECM determines the lock-up status of the torque converter by comparing the engine speed (NE) to the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing the input turbine rpm (NT) to the counter gear rpm (NC). When conditions are appropriate, the ECM 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 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 shift solenoid valve SL 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.


INSPECTION PROCEDURE

Tech Tips

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.


  1. PERFORM ACTIVE TEST


    1. Warm up the engine.

    2. Turn the ignition switch off.

    3. Connect the intelligent tester to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the intelligent tester on.

    6. Enter the following menus: Powertrain / Engine and 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]


      • Throttle valve opening angle: Less than 20%

      • Vehicle speed:60 km/h (37 mph) or more, and 6th gear

      Tech Tips


      • 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.

      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.)

      A01ET5GE29

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. 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.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK TRANSMISSION WIRE


    1. A01EXB1E55

      Remove the wiring harness connector from the transaxle.

    2. 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
      Text in Illustration
      *a

      Component without harness connected

      (Transmission Wire)

    NG

    INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE) Click here

    OK

  3. INSPECT SHIFT SOLENOID VALVE SL (OPERATION)


    1. A01ET8NE02
      Text in Illustration
      *1 Shift Solenoid Valve SL

      Remove shift solenoid valve SL.

    2. 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.

    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)


    1. A01EXYDE02
      Text in Illustration
      *1 Shift Solenoid Valve SL

      Remove shift solenoid valve SL.

    2. 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

    NG

    REPLACE SHIFT SOLENOID VALVE SL Click here

    OK

    REPLACE TRANSMISSION WIRE Click here