СИСТЕМА АВТОМАТИЧЕСКОЙ ТРАНСМИССИИ С ЭЛЕКТРОННЫМ УПРАВЛЕНИЕМ, Diagnostic DTC:P0781

DTC Code DTC Name
P0781 1-2 Shift (1-2 Shift Valve)

DESCRIPTION

The 1-2 shift valve performs shifting to 1st gear and other gears.

A01E068E01
DTC No. DTC Detection Condition Trouble Area
P0781 Gear required by the ECM does not match the actual gear when driving (2 trip detection logic*1, 1 trip detection logic*2)

  • Valve body is blocked up or stuck (1-2 shift valve)

  • Shift solenoid valve SLT remains open or closed

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

MONITOR DESCRIPTION

This DTC indicates that the 1-2 shift valve in the valve body is locked in the direction that the spring compresses.

The ECM commands gear shifts by turning the shift solenoid valves ON/OFF and switching oil pressure to the valves in the valve body.

The ECM calculates the actual transmission gear by comparing the signals from the input speed sensor (NT) and the output speed sensor (SP2). The ECM can detect mechanical problems in the shift solenoids, valve body, and the transmission clutches, brakes, and gears. If the ECM detects that the actual gear position and the commanded gear position are different, it will illuminate the MIL and store the DTC.

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0781)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch ON and push the intelligent tester main switch ON.

    3. Enter the following menus: Powertrain / Engine and ECT / DTC / Current or Pending.

    4. Read the DTCs using the intelligent tester.

      Result
      Display (DTC output) Proceed to
      Only P0781 is output A
      P0781 and other DTCs B

      Tech Tips

      If any other codes besides P0781 are output, perform troubleshooting for those DTCs first.


    B

    GO TO DTC CHART

    A

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

    Tech Tips

    Performing the intelligent tester's Active Test allows relay, Vacuum Switching Valve (VSV), actuator and other item values to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to save time. The Data List can be displayed during the Active Test.


    1. Warm up the engine.

    2. Turn the ignition switch OFF.

    3. Connect the intelligent tester to the DLC3.

    4. Turn the ignition switch ON and push the tester main switch ON.

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test.

    6. Follow the instructions on the tester and read the Active Test.

    Tech Tips

    While driving, the shift position can be forcibly changed with the intelligent tester.

    Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem Click here.

    Item Test Details Diagnostic Note
    Control the Shift Position

    [Test Details]

    Operate shift solenoid valve and set each shift position by yourself

    [Vehicle Condition]

    50 km/h (31 mph) or less

    [Other information]


    • Press "→" button: Shift up

    • Press "←" button: Shift down

    		 Possible to check operation of shift solenoid valves

    Tech Tips


    • This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.

    • The 4th to 5th up-shift must be performed with the accelerator pedal released.

    • The 5th to 4th down-shift must be performed with the accelerator pedal released.

    • Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.

    • The shift position commanded by the ECM is shown in the Data List (shift status) display on the intelligent tester.

    OK
    Gear position changes in accordance with the tester command.

    NG

    REPLACE TRANSMISSION VALVE BODY ASSEMBLY

    OK

  3. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

    A01E342E01

    Note


    • Perform the test at the normal operating ATF temperature: 50 to 80°C (122 to 176°F).

    • Be careful to prevent SST's hose from interfering with the exhaust pipe.

    • Perform the test with the A/C OFF.

    Tech Tips

    Performing the intelligent tester's Active Test allows relay, Vacuum Switching Valve (VSV), actuator and other items values to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to save time. The Data List can be displayed during the Active Test.


    1. Remove the test plug on the transmission case center right side and connect SST.

      SST
      09992-00095   ( 09992-00231, 09992-00271 )

    2. Connect the intelligent tester to the DLC3.

    3. Start the engine and warm it up.

    4. Measure the line pressure with SST.

    5. Turn the intelligent tester ON.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test.

    7. Follow the instructions on the tester and perform the Active Test.

    8. Measure the line pressure with SST.

      Item Test Details Diagnostic Note
      Control the Line Pressure Up*

      [Test Details]

      Operate shift solenoid SLT and raise line pressure

      [Vehicle Condition]


      • Vehicle stopped

      • IDL: ON

      Tech Tips

      OFF: Line pressure up (when Active Test "Control the Line Pressure Up" is performed, ECM commands SLT solenoid to turn OFF)

      ON: No action (normal operation)

      		 -

      Tech Tips

      *: "Control the Line Pressure Up" in the Active Test is performed to check the line pressure changes by connecting SST to the automatic transmission, which is used in the Hydraulic Test Click here as well. Please note that the pressure values in the Active Test and Hydraulic Test are different.


    NG

    REPLACE SHIFT SOLENOID VALVE SLT

    OK

  4. CLEAR DTC AND PERFORM RUNNING TEST


    1. Clear the DTC, and check for the DTC again after conducting the "Test Monitor Drive Pattern for ECT" Click here.

      OK
      No DTC code

    NG

    REPLACE TRANSMISSION VALVE BODY ASSEMBLY

    OK

    END