AUTOMATIC TRANSMISSION SYSTEM(for 1GR-FE), 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, transmission revolution sensor (NT), transmission revolution sensor (SP2) 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 transmission revolution sensor (NT), transmission revolution sensor (SP2) 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, transmission valve body assembly and torque converter assembly 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

  • Transmission wire

  • Transmission valve body assembly is blocked

  • Torque converter assembly

  • Automatic transmission assembly (clutch, brake or gear etc.)

  • Line pressure is too low

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the ECM based on the transmission revolution sensor (NT), transmission revolution sensor (SP2), 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 speed (NT). The ECM calculates the actual transmission gear by comparing the input turbine speed (NT) to the output shaft speed (SP2). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to shift solenoid valve SL. When shift solenoid valve 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 illuminate 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 speed 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 70 rpm more than the input turbine speed.)

  • There is no difference in rotation speed 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.)

CAUTION / NOTICE / HINT

Note

Perform registration and/or initialization when parts related to the automatic transmission are replaced Click here.

Tech Tips

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Perform the Lock-up Function in Road Test Click here.*1

  2. Turn the engine switch off.

  3. Perform step (*1) again.

  4. Check for DTCs again Click here.


  1. ACTIVE TEST

    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.


    1. Warm up the engine.

    2. Turn the engine switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

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

    7. According to the display on the GTS, perform the Active Test.

      Engine and ECT
      Tester Display Test Part Control Range Diagnostic Note
      Activate the Lock Up Controls the shift solenoid valves SLU and SL to set the automatic transmission to the lock-up condition. ON/OFF

      Can be used to check shift solenoid valves SLU and SL operation.

      [Vehicle Condition]


      • Throttle valve opening angle: Less than 10%

      • Vehicle speed: 80 km/h (50 mph) or more

      Tech Tips


      • This test can be conducted when the vehicle speed is 80 km/h (50 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 the accelerator pedal in order to decelerate, but do not fully release the pedal. (Fully releasing the pedal will close the throttle valve and lock-up may be turned off.)

      B001GMRE41

PROCEDURE


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


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

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

    5. Read the DTCs using the GTS.

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

      Tech Tips

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


    B
    A
  2. INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL)


    1. B001H2ME54
      Text in Illustration
      *a

      Component without harness connected

      (Transmission Wire)

      Disconnect the transmission wire connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (SL) - Body ground 20°C (68°F) 11 to 15 Ω

    NG
    OK
  3. INSPECT SHIFT SOLENOID VALVE SL (OPERATION)


    1. B001EKNE09
      Text in Illustration
      *1 Shift Solenoid Valve SL

      Remove shift solenoid valve SL Click here.

    2. Apply 12 V battery voltage to the shift solenoid valve and check that the valve moves and makes an operating noise.

      OK
      Measurement Condition Specified Condition

      • Battery positive (+) → Shift solenoid valve SL connector

      • Battery negative (-) → Shift solenoid valve SL body

      Valve moves and makes an operating noise

    NG
    OK
  4. INSPECT TRANSMISSION VALVE BODY ASSEMBLY


    1. Check the transmission valve body assembly Click here.

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

    NG
    OK
  5. INSPECT TORQUE CONVERTER ASSEMBLY


    1. Check the torque converter assembly Click here.

      OK
      The torque converter operates normally.

    OK
    NG
  6. INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)


    1. B001HWPE01
      Text in Illustration
      *1 Shift Solenoid Valve SL

      Remove shift solenoid valve SL Click here.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Shift solenoid valve SL connector terminal - Shift solenoid valve SL body 20°C (68°F) 11 to 15 Ω

    OK
    NG