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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Engine Mechanical >> Starter >> Stop And Start System - Diagnostic Codes (1 Of 3) >> Stop And Start System >> DTC P0942-96: Hydraulic Pressure Unit Component Internal Failure [12/2019 - 10/2022] >> Procedure

DTC P0942-96: Hydraulic Pressure Unit Component Internal Failure [12/2019 - 10/2022]: Procedure

  1. CHECK ENGINE STOP AND START ECU (EMOP AND EGND TERMINAL WAVEFORM) 
    1. Drive the vehicle to warm up the engine and automatic transaxle fluid.

      HINT: 

      The oil pump with solenoid assembly may not operate properly if the automatic transaxle fluid temperature is low. Make sure to warm up the automatic transaxle fluid before performing the Active Test. (Automatic transaxle fluid temperature: 25°C (77°F) or higher)

    2. Turn the ignition switch to ON.

      HINT: 

      Do not start the engine.

    3. Connect an oscilloscope to the EMOP, EGND and GND1 terminals of the engine stop and start ECU connector.
      GTY909763Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Engine Stop and Start ECU)      		 - -
    4. Check the waveform while performing the Active Test.

      Powertrain > Stop and Start > Active Test 

      Tester Display
      Electromagnetic Oil Pump
      Item Condition
      Tester Connection H66-8 (EGND) - A33-8 (GND1)
      H66-9 (EMOP) - A33-8 (GND1)
      Tool Setting 10 V/DIV., 20 ms./DIV.
      Condition
      • Ignition switch ON (engine is stopped)
      • Active Test "Electromagnetic Oil Pump" being performed

      Standard

      The waveform is similar to that shown in the illustration.

      GTY862700Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE OIL PUMP WITH SOLENOID ASSEMBLY 

    1. for 2WD Models:

      Refer to DISASSEMBLY [12/2019 - 10/2022]

    2. for AWD Models:

      Refer to DISASSEMBLY [12/2019 - 10/2022]

    Result: 

    OK 

    See step  2

  2. CLEAR DTC 
    1. Clear the DTCs.

      Powertrain > Stop and Start > Clear DTCs 

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  3

  3. CHECK DTC OUTPUT 
    1. Start the engine.
    2. Perform a road test.
    3. Read the DTCs.

      Powertrain > Stop and Start > Trouble Codes 

      Result

      Result Proceed to
      DTC P0942-96 is output A
      DTC P0942-96 is not output B

    Result: 

    A 

    REPLACE ENGINE STOP AND START ECU. Refer to  REMOVAL [12/2019 - 10/2022] 

    Result: 

    B 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

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