ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION SYSTEM, Diagnostic DTC:P0741/64

DTC Code DTC Name
P0741/64 Torque Converter Clutch Solenoid Performance (Shift Solenoid Valve SL)

DESCRIPTION

The TCM uses the signals from the throttle position sensor, mass 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.

A003EC4E01
DTC No. DTC Detection Condition Trouble Area
P0741/64

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 75 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 OTHER DTCS OUTPUT (IN ADDITION TO DTC P0741/64)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to the ON position.

    3. Turn on the tester.

    4. Select the item "Power train / ECT / DTC / Current or Pending".

    5. Read the DTCs using the intelligent tester.

      Result
      Display (DTC output) Proceed to
      Only "P0741/64" is output A
      "P0741/64" and other DTCs B

      Tech Tips


      • If any other codes besides "P0741/64" are output, perform troubleshooting for those DTCs first.

      • When not using the intelligent tester, refer to DTC CHECK / CLEAR Click here.


    B

    GO TO DTC CHART

    A

  2. INSPECT SHIFT SOLENOID VALVE SL


    1. A003FJ2E01

      Remove the shift solenoid valve SL.

    2. Measure the resistance.

      Standard resistance
      Tester Connection

      Specified Condition

      20°C (68°F)
      Solenoid Connector (SL) - Solenoid Body (SL) 11 to 15 Ω

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

      OK
      The solenoid makes an operating sound.

    NG

    REPLACE SHIFT SOLENOID VALVE SL

    OK

  3. INSPECT 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

    OK
    The torque converter clutch operates normally.

    NG

    REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY

    OK

    REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY