AUTOMATIC TRANSMISSION 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, transmission revolution sensor (NT), transmission revolution sensor (SP2) and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.

A01FGO4E01

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

DTC No. 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 assembly

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

  • Line pressure is too low

MONITOR DESCRIPTION

Torque converter assembly lock-up is controlled by the ECM based on the transmission revolution sensor (NT), transmission revolution sensor (SP2), engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and gear selection. The ECM determines the lock-up status of the torque converter assembly by comparing the engine rpm (NE) to the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm (NT) to output shaft rpm (SP2). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to the shift solenoid SLU. When the SLU is turned on, it applies pressure to the lock-up relay valve and locks the torque converter assembly.

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 the 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


  1. ACTIVE TEST

    Tech Tips

    Using the GTS to perform Active Test 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 Test early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing 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) position.

    5. Turn the GTS on.

    6. Select the item "Powertrain / Engine and ECT / Active Test".

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

      Item Test Details Diagnostic Note
      Activate the Lock Up

      [Test Details]

      Control the shift solenoid SLU to set the automatic transmission to the lock-up condition.

      [Vehicle Condition]


      • Throttle valve opening angle: Less than 35 %

      • Vehicle Speed: 60 km/h (37 mph) or more

      		 Possible to check the SLU operation.

      Tech Tips


      • This test can be conducted when the vehicle speed is 58 km/h (36 mph) or more.

      • This test can be conducted with the 5th or 6th gear.

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

      A01FEGCE19

      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 automatically.)

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) position and push the GTS main switch ON.

    3. When you use GTS:

      Select the item "Powertrain / Engine and ECT / Trouble Codes".

    4. Read the DTCs using the GTS.

      Result
      Display (DTC output) Proceed to
      Only "P2757" is output A
      "P2757" and other DTCs 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. A01FDHVE09
      Text in Illustration
      *1 Shift Solenoid Valve SLU

      Remove the shift solenoid valve SLU.

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

      Standard resistance
      Tester Connection

      Specified Condition

      20°C (68°F)
      1 - 2 5.0 to 5.6 Ω

    3. Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve.

      OK
      The solenoid 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 are no foreign objects on each valve.

    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

    REPAIR OR REPLACE AUTOMATIC W/TRANSFER TRANSMISSION ASSEMBLY Click here