ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION SYSTEM (for 1KD-FTV), Diagnostic DTC:P0741

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

DESCRIPTION

The TCM uses the signals from the throttle position sensor, air-flow meter and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.

Then the TCM compares the engagement condition of the lock-up clutch with the lock-up schedule in the TCM memory to detect mechanical trouble of the shift solenoid valve SL, valve body and torque converter clutch.

A01DVIUE01
DTC No. DTC Detection Condition Trouble Area
P0741 Lock-up does not occur when driving in the lock-up range (normal driving at 80 km/h [50 mph]), or lock-up remains ON in the lock-up OFF range (2-trip detection logic)

  • Shift solenoid valve SL is stuck open or closed

  • Valve body is blocked

  • Torque converter clutch

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

  • Line pressure is too low

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the TCM based on O/D direct clutch (input) speed sensor NC0, output speed sensor SP2, throttle position, engine temperature, transmission temperature, and gear selection. The TCM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to the input shaft rpm (NC0) or output shaft rpm (SP2). The TCM calculates the actual transmission gear by comparing input shaft rpm (NC0) to output shaft rpm (SP2). When conditions are appropriate, the TCM requests "lock-up" by applying control voltage to shift solenoid SL. When the SL is turned on, solenoid SL applies pressure to the lock-up relay valve and locks the torque converter clutch.

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 the shift solenoid valve SL or lock-up system performance.

The TCM will turn on the MIL and store the DTC.

Example:

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


  1. There is a difference in rotation between before and after torque converters even when the TCM commands lock-up.

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

  2. There is no difference in rotation between before and after torque converters even when the TCM commands lock-up off.

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

INSPECTION PROCEDURE

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch ON and push the intelligent tester main switch ON.

    3. Enter the following menus: Powertrain / ECT / DTC / Current or Pending.

    4. Read the DTCs using the intelligent tester.

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

      Tech Tips

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


    B

    GO TO DTC CHART

    A

  2. INSPECT SHIFT SOLENOID VALVE SL


    1. A01E346E04

      Remove the shift solenoid valve SL.

    2. Measure the resistance of the solenoid value.

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

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

    4. Check the operating noise of the solenoid valve.

      OK
      Solenoid makes operating noise.

    NG

    REPLACE SHIFT SOLENOID VALVE SL

    OK

  3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY


    1. Check the transmission valve body assembly.

      OK
      There are no foreign objects on each valve.

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY

    OK

  4. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY


    1. Check the torque converter clutch assembly.

      OK
      The torque converter clutch operates normally.

    NG

    REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY

    OK

    REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY