AUTOMATIC TRANSMISSION SYSTEM(for 1KD-FTV), Diagnostic DTC:P2757

DTC Code DTC Name
P2757 Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)

DESCRIPTION

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

B001FNBE01

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

DTC Code DTC Detection Condition Trouble Area
P2757 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 SLU remains open or closed

  • Valve body is blocked

  • Torque converter clutch assembly

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

  • Line pressure is too low

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the TCM based on the turbine (input) speed sensor NT, output speed sensor SP2, engine speed, engine load, engine temperature, vehicle speed, transmission 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 speed (NT). The TCM calculates the actual transmission gear by comparing the input turbine speed (NT) to the output shaft speed (SP2). When conditions are appropriate, the TCM requests lock-up by applying control voltage to shift solenoid SLU. When shift solenoid valve SLU is turned on, it 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 shift solenoid valve SLU or the lock-up system performance.

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

Example:

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


CAUTION / NOTICE / HINT


  1. ACTIVE TEST

    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. 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 / ECT / Active Test.

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

      ECT
      Tester Display Test Part Control Range Diagnostic Note
      Activate the Lock Up Control shift solenoid valve SLU to set automatic transmission to lock-up ON or OFF

      Possible to check shift solenoid valve SLU operation.

      [Vehicle Condition]


      • Throttle valve opening angle: Less than 35%

      • 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.

      • This test can be conducted with the 5th gear.

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

      B001GMRE01

      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 automatically.)

PROCEDURE


  1. CHECK DTC OUTPUT (IN ADDITION TO DTC P2757)


    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 / ECT / DTC.

    5. Read the DTCs using the tester.

      Result
      Result Proceed to
      Only P2757 is output A
      P2757 and other DTCs are output B

      Tech Tips

      If any other codes besides P2757 are output, perform troubleshooting for those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. INSPECT SHIFT SOLENOID VALVE SLU


    1. B001DSBE05
      Text in Illustration
      *a

      Component without harness connected

      (Shift Solenoid Valve SLU)

      Remove shift solenoid valve SLU.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 - 2 20°C (68°F) 5.0 to 5.6 Ω

    3. 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 (+) with a 21 W bulb → Terminal 2

      • Battery negative (-) → Terminal 1

      		 Valve moves and makes an operating noise

    NG

    REPLACE SHIFT SOLENOID VALVE SLU Click here

    OK

  3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY


    1. Check the transmission valve body assembly Click here.

      OK
      There are no foreign objects on any valve.

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

    OK

  4. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY


    1. Check the torque converter clutch assembly Click here.

      OK
      The torque converter clutch operates normally.

    OK

    REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY Click here

    NG

    REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY Click here