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 ECM 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.

A01G8I5E01

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 SLU, valve body and torque converter mechanical problems.

DTC No. DTC Detection Condition Trouble Area
P2757

  • Lock-up does not occur when requested.

  • Lock-up occurs when shift solenoid valve SLU is requested to turn on in the lock-up range.

(2-trip detection logic)

  • Shift solenoid valve SLU remains open or closed

  • Valve body is blocked

  • Torque converter assembly

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

  • Line pressure is too low

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the ECM based on the turbine (input) speed sensor NT, output speed sensor NC, 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 input turbine speed (NT) to output shaft speed (NC). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to shift solenoid SLU. When SLU 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 SLU or lock-up system performance.

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

Example:

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


INSPECTION PROCEDURE

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. 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 / Engine and ECT / Active Test.

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

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

      Can be used to check SLU and SL solenoid operation.

      [Vehicle Condition]


      • Throttle valve opening angle: Less than 20%

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

      Tech Tips


      • This test can be conducted 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.

      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.)

      A01G75VE29

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 / Engine and ECT / Trouble Codes.

    5. Read the DTCs using the GTS.

      Result
      Display (DTC output) 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. A01G670E01
      Text in Illustration
      *1 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. Connect a battery positive (+) lead with a 21 W bulb to terminal 2 and a negative (-) lead to terminal 1 of the solenoid valve connector. Then check that the valve moves and makes an operating sound.

      OK
      Valve moves and makes an operating sound.

    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.

    NG

    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 operates normally.

    NG

    REPLACE TORQUE CONVERTER ASSEMBLY Click here

    OK

    REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Click here