СИСТЕМА АВТОМАТИЧЕСКОЙ ТРАНСМИССИИ, Diagnostic DTC:P0781

Информация добавлена 08-08-2017

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

DESCRIPTION


DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0781 1-2 Shift (1-2 Shift Valve) Gear required by the ECM does not match the actual gear when driving (2-trip detection logic).

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

  • Shift solenoid valve SLT remains open or closed

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

 Comes on DTC stored

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 controls the oil pressure applied 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 output speed sensor SP2. The ECM can detect mechanical problems in the shift solenoids, valve body and automatic transmission (clutch, brake, gear, etc.). If the ECM detects that the actual gear position and commanded gear position are different, it will illuminate the MIL and store the DTC.

PROCEDURE


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


    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.


      Powertrain > Engine and ECT > Trouble Codes

    5. Read the DTCs using the GTS.

      Result
      Result Proceed to
      Only P0781 is output A
      P0781 and other DTCs are output B

      Tech Tips

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


    B

    GO TO DTC CHART Click here

    A

  2. PERFORM ACTIVE TEST USING GTS (RUNNING TEST)

    CAUTION:

    This test should always be performed with at least 2 people.

    Note


    • Perform the test while the ATF temperature is 50 to 80°C (122 to 176°F).

    • Perform the test with the A/C turned off.

    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. Connect the GTS to the DLC3.

    2. Clear the DTCs Click here.

    3. Warm up the engine.

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

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

      Tech Tips

      While driving, the shift position can be forcibly changed with the GTS.Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem Click here.


      Powertrain > Engine and ECT > Active Test
      Tester Display
      Control the Shift Position

      Powertrain > Engine and ECT > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Control the Shift Position Operate shift solenoid valve and set each shift position

      • Press "→" button: Shift up

      • Press "←" button: Shift down

      Possible to check operation of the shift solenoid valves.

      [Vehicle Condition]

      50 km/h (31 mph) or less.

      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 display on the GTS.

      OK
      Gear position changes in accordance with the GTS command.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

    OK

  3. PERFORM ACTIVE TEST USING GTS (SHIFT SOLENOID VALVE SLT)

    Note


    • Perform the test while the ATF temperature is 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

    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 bevery 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. A01A5SDN04

      Remove the test plug from the transmission case and connect SST.

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

    2. Connect the GTS to the DLC3.

    3. Start the engine and warm it up.

    4. Measure the line pressure with SST.

    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.

    8. Measure the line pressure.


      Powertrain > Engine and ECT > Active Test
      Tester Display
      Activate the Solenoid (SLT)

      Powertrain > Engine and ECT > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Activate the Solenoid (SLT) Operate shift solenoid SLT and raise line pressure

      ON or OFF

      Tech Tips


      • OFF: Line pressure up (when Active Test "Activate the Solenoid (SLT)" is performed, ECM commands SLT solenoid to turn OFF)

      • ON: No action (normal operation)

      [Vehicle Condition]


      • Vehicle stopped.

      • Engine idling.

      Tech Tips

      Activate the Solenoid (SLT) 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. Note that the pressure values in the Active Test and Hydraulic Test are different.

      OK
      The line pressure changes as specified when performing the Active Test.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SHIFT SOLENOID VALVE SLT Click here

    OK

  4. CLEAR DTC AND PERFORM RUNNING TEST


    1. Clear the DTCs Click here.


      Powertrain > Engine and ECT > Clear DTCs

    2. Check for DTCs again after conducting the Monitor Drive Pattern Click here.

      OK
      No DTC code output.

      Powertrain > Engine and ECT > Trouble Codes
      Result
      Proceed to
      OK
      NG

    OK

    END

    NG

    REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY Click here