AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P2757

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

SYSTEM DESCRIPTION

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

A01IKL4C01
*a Spool Valve *b Sleeve
*c Solenoid Coil *d Hydraulic Pressure
*e Current - -

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

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P2757 Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)

1. Diagnosis Condition 2. Malfunction Status 3. Malfunction Time 4. Other


    DTC Detection Condition 1:

  1. Engine coolant temperature is 40°C (104°F) or more, ATF temperature is -10°C (14°F) or more and the vehicle is being driven with the shift lever in D (no malfunctions are detected in the shift solenoid valves (SL1, SL2, SL3, SL4 and SLU), transmission revolution sensor (NT, NC), coolant temperature sensor, knock control sensor, electronic throttle, or CAN2).

  2. Both of the following conditions (a) and (b) are met when the TCM commands lock-up ON:


    1. Lock-up does not occur

    2. No. 3 ATF pressure switch is OFF

  3. 3.5 seconds

  4. 2-trip detection logic


    DTC Detection Condition 2:

  1. Engine coolant temperature is 40°C (104°F) or more, ATF temperature is -10°C (14°F) or more and the vehicle is being driven with the shift lever in D (no malfunctions are detected in the shift solenoid valves (SL1, SL2, SL3, SL4 and SLU), transmission revolution sensor (NT, NC), coolant temperature sensor, knock control sensor, electronic throttle, or CAN2).

  2. Both of the following conditions (a) and (b) are met when the TCM commands lock-up OFF:


    1. Lock-up occurs

    2. No. 3 ATF pressure switch is ON

  3. 1.8 seconds

  4. 2-trip detection logic

  • Shift solenoid valve SLU remains open or closed

  • Transmission valve body assembly is blocked

  • Torque converter assembly

  • Automatic transaxle assembly (clutch, brake, gear, etc.)

  • Line pressure is too low

 Comes on DTC stored

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the TCM based on the input speed sensor NT, output speed sensor NC, engine speed, engine load, engine temperature, vehicle speed, transmission fluid temperature, and gear selection signal. The TCM determines the lock-up status of the torque converter by comparing the engine speed signal (NE) to the input speed sensor NT signal and calculates the actual transmission gear by comparing the input speed sensor NT signal to the output speed sensor NC signal. When conditions are appropriate, the TCM requests "lock-up" by applying control voltage to the shift solenoid valve SLU. When the 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 does not detect lock-up after lock-up has been requested or if it detects lock-up when it is not requested, it interprets this as a malfunction of the shift solenoid valve SLU or in lock-up system performance, illuminates the MIL and stores this DTC.

Example:

If any of the following conditions are met, the system judges it as a malfunction.


CAUTION / NOTICE / HINT

Note

Perform registration and/or initialization when parts related to the automatic transaxle are replaced.

Click here

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.

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


    1. Perform the Lock-up Function inspection in Road Test.

      Click here

    2. Turn the engine switch off.

    3. Perform step (a) again.

    4. Check for DTCs again.

      Click here


  1. ACTIVE TEST


    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 / ECT / Active Test / Activate the Lock Up.

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


      Powertrain > ECT > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Activate the Lock Up Control the shift solenoid valves SLU and SL to control the automatic transaxle lock-up condition. ON/OFF

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


        [Vehicle Condition]

      • Throttle valve opening angle: Less than 20%

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

      Powertrain > ECT > Active Test
      Tester Display
      Activate the Lock Up

      Tech Tips


      • This Active Test can be performed 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.

      A01IFWRE10

      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.)

PROCEDURE


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


    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 / ECT / Trouble Codes.


      Powertrain > ECT > Trouble Codes

    5. Read the DTCs using the GTS.

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

      Tech Tips

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


    B

    GO TO DTC CHART Click here

    A

  2. INSPECT SHIFT SOLENOID VALVE SLU


    1. B006L78C02
      *1 Shift Solenoid Valve SLU

      Remove the shift solenoid valve SLU.

      Click here

    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. Connect a positive (+) lead from the battery with a 21 W bulb to terminal 2 and a negative (-) lead to terminal 1 of the shift solenoid valve connector. Check that the valve moves and makes an operating sound.

      OK
      Valve moves and makes an operating sound.
      Result
      Proceed to
      OK
      NG

    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 is no foreign matter on each valve and they operate smoothly.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

    OK

  4. INSPECT TORQUE CONVERTER ASSEMBLY


    1. Check the torque converter assembly.

      Click here

      OK
      The torque converter assembly is normal.
      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Click here

    NG

    REPLACE TORQUE CONVERTER ASSEMBLY Click here