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Home >> Lexus >> 2008 >> IS 250 RWD, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (A760H Automatic Transaxle) >> Automatic Transmission System >> DTC P0781 1-2 Shift (1-2 Shift Valve) >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0781) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) position and push the Techstream main switch ON.
    3. When you use Techstream:

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

    4. Read the DTCs using the Techstream.

      Result 

      RESULT CHART

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

      HINT:

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

    B: GO TO DTC CHART 

    A: Go to next step 

  2. PERFORM ACTIVE TEST BY TECHSTREAM 

    HINT:

    Using the Techstream 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 Techstream to the DLC3.
    4. Turn the engine switch on (IG) position.
    5. Turn the Techstream on.
    6. Select the item "Powertrain / Engine and ECT / Active Test".
    7. According to the display on tester, perform the "Active Test".

      HINT:

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

      Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem (See DATA LIST / ACTIVE TEST  ).

      DIAGNOSTIC NOTE

      Item Test Details Diagnostic Note
      Control the Shift Position [Test Details]
      Operate the shift solenoid valve and set the each shift position by yourself.
      [Vehicle Condition]
      • IDL: ON (4th, 5th and 6th)
      • Less than 50 km/h (31 mph)

      [Others]
      • Press "→" button: Shift up
      • Press "←" button: Shift down
      		 Possible to check the operation of the shift solenoid valves.

      HINT:

      • This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.
      • The 4th to 5th and 5th to 6th up-shiftings must be performed with the accelerator pedal released.
      • The 6th to 5th and 5th to 4th down-shiftings 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 Techstream.
      • Gear positions in the event of a solenoid valve mechanical problem:
        GEAR POSITION CHART

        Tester command gear shift 1st 2nd 3rd 4th 5th 6th
        Actual gear position under malfunction ↑ 1st ↑ 3rd (1) (1)
        (1) Neutral

        OK: 

        Gear position changes in accordance with the tester command. 

    NG: REPLACE TRANSMISSION VALVE BODY ASSEMBLY 

    OK: Go to next step 

  3. PERFORM ACTIVE TEST BY TECHSTREAM (SHIFT SOLENOID VALVE SLT) 
    NOTE:
    • Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature: 50 to 80°C (122 to 176°F)
    • Be careful to prevent SST hose from interfering with the exhaust pipe.
    • This check must be conducted after checking and adjusting engine.
    • Perform under condition that A/C is OFF.

    HINT:

    Using the Techstream 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. Turn the engine switch off.
    2. Lift the vehicle up.
    3. Remove the test plug on the transmission case center right side and connect SST.

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

    4. Lower the vehicle.
    5. Fully apply the parking brake and chock the 4 wheels.
    6. Connect the Techstream to the DLC3.
    7. Start the engine.
    8. Warm up the ATF (Automatic Transmission Fluid).
    9. Measure the line pressure when the engine is idling.
    10. Turn the Techstream on.
    11. Select the item "Powertrain / Engine and ECT / Active Test".
    12. According to the display on tester, perform the "Active Test".
      Fig 1: Measuring Line Pressure With SST
      G05289558Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    13. Measure the line pressure with SST.
      ITEM TEST DETAILS

      Item Test Details
      Activate the Solenoid (SLT)(1) [Test Details]
      Operate the shift solenoid SLT and raise the line pressure.
      [Vehicle Condition]
      • Vehicle Stopped.
      • IDL: ON

      HINT:
      OFF: Line pressure up (When the active test of "Activate the Solenoid (SLT)" is performed, the ECM commands the SLT solenoid to turn off).
      ON: No action (normal operation)
      (1) "Activate the Solenoid (SLT)" in the Active Test is performed to check the line pressure changes by connecting the SST to the automatic transmission, which is used in the HYDRAULIC TEST  as well.

      HINT:

      The pressure values in Active Test and HYDRAULIC TEST are different from each other.

      OK: 

      The line pressure changes as specified when performing the Active Test. 

    NG: REPLACE SHIFT SOLENOID VALVE SLT 

    OK: Go to next step 

  4. CLEAR THE DTC AND RUNNING TEST 
    1. Clear the DTC, and check DTC again after conducting the "MONITOR DRIVE PATTERN FOR ECT TEST" (See MONITOR DRIVE PATTERN  ).

      OK: 

      No DTC code 

    NG: REPLACE TRANSMISSION VALVE BODY ASSEMBLY 

    OK: END 

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