STOP AND START SYSTEM, Diagnostic DTC:P0942

DTC Code DTC Name
P0942 Hydraulic Pressure Unit

DESCRIPTION

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DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory
P0942 Hydraulic Pressure Unit

The following condition continues for 0.032 seconds or more (2 trip detection logic):


  • Difference between turbine speed and output shaft speed is 330 rpm or more within 0.2 seconds after engine restarted during idling stop when shift lever is in D.

  • Electromagnetic oil pump

  • Engine stop and start ECU

 Blinks DTC stored

CONFIRMATION DRIVING PATTERN

Tech Tips

DTCs for the stop and start system are not cleared even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.

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  1. Tech Tips


    • If the cable is disconnected from the battery terminal, stop and start control is prohibited until refresh charge is completed.

      In this case, let the vehicle idle with the battery temperature at 11°C (51°F) or higher for 5 to 60 minutes to complete the refresh charge. (The refresh charge is complete when the Data List item Status of Battery Charge Control changes from "Refresh Charge Mode".)

    • If the GTS is not available and the Data List item Status of Battery Charge Control cannot be checked, charge the battery by idling the engine for approximately 5 to 60 minutes or driving the vehicle, and then drive the vehicle and check that stop and start control operates.

      If the engine is started with the hood open, the system determines that a jump start has occurred. Therefore, make sure that the hood is closed before starting the engine and driving the vehicle.

    • After the refresh charge completes, turn the engine switch off, wait for at least 30 seconds, and then start the engine again.

      If the vehicle enters refresh charge mode again while the engine is idling, the initial refresh charge did not properly complete, so wait for the refresh charge to complete.

    • Allow the engine to idle for 3 minutes after the engine warms up and check that the engine speed is within 50 rpm of the target idle speed.

    CONFIRMATION AFTER TROUBLESHOOTING


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

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      Powertrain > Stop and Start > Clear DTCs

    4. Start the engine and warm it up.

    5. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

    6. Depress the brake pedal and stop the vehicle.

    7. Keep the engine stopped by stop and start control. (Keep the shift lever in D.)

    8. Release the brake pedal with the shift lever in D to start the engine.

    9. Check that no DTCs are output.

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      Powertrain > Stop and Start > Trouble Codes

  2. Tech Tips


    • If the cable is disconnected from the battery terminal, stop and start control is prohibited until refresh charge is completed.

      In this case, let the vehicle idle with the battery temperature at 11°C (51°F) or higher for 5 to 60 minutes to complete the refresh charge. (The refresh charge is complete when the Data List item Status of Battery Charge Control changes from "Refresh Charge Mode".)

    • If the GTS is not available and the Data List item Status of Battery Charge Control cannot be checked, charge the battery by idling the engine for approximately 5 to 60 minutes or driving the vehicle, and then drive the vehicle and check that stop and start control operates.

      If the engine is started with the hood open, the system determines that a jump start has occurred. Therefore, make sure that the hood is closed before starting the engine and driving the vehicle.

    • After the refresh charge completes, turn the engine switch off, wait for at least 30 seconds, and then start the engine again.

      If the vehicle enters refresh charge mode again while the engine is idling, the initial refresh charge did not properly complete, so wait for the refresh charge to complete.

    STOP AND START SYSTEM OPERATION CHECK


    1. Start the engine and warm it up.

    2. Turn the air conditioning system off.

    3. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

    4. Depress the brake pedal and stop the vehicle.

    5. Allow the engine to stop by stop and start control. (Keep the shift lever in D.)

    6. Release the brake pedal with the shift lever in D to start the engine.

WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note

When the electromagnetic oil pump is replaced, check the electromagnetic oil pump.

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Tech Tips

Using the GTS, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting.

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PROCEDURE


  1. CHECK ENGINE STOP AND START ECU (EMOP TERMINAL WAVEFORM)


    1. Drive the vehicle to warm up the engine and automatic transmission fluid.

      Tech Tips

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

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

      Tech Tips

      Do not start the engine.

    4. Turn the GTS on.

    5. Connect an oscilloscope to terminals G127-9 (EMOP), G127-8 (EGND) and G125-8 (GND1).

      B0024ANC91
      *a

      Component with harness connected

      (Engine Stop and Start ECU)

      		 - -

    6. Enter the following menus: Powertrain / Stop and Start / Active Test / Electromagnetic Oil Pump.

    7. B0028UUE01
      *1 10 V/DIV.
      *2 20 ms./DIV.

      Check the waveform while performing the Active Test.

      Item Condition
      Tester Connection

      G127-9 (EMOP) - G125-8 (GND1)

      G127-8 (EGND) - G125-8 (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.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ELECTROMAGNETIC OIL PUMP Click here

    OK

  2. CLEAR DTC


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Stop and Start / Trouble Codes.

    5. Clear the DTCs.


      Powertrain > Stop and Start > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK DTC OUTPUT


    1. Turn the ignition switch to ON.

    2. Start the engine.

    3. Perform a road test.

    4. Enter the following menus: Powertrain / Stop and Start / Trouble Codes.

    5. Read the DTCs.


      Powertrain > Stop and Start > Trouble Codes
      Result
      Result Proceed to
      DTC P0942 is output A
      DTC P0942 is not output B

    A

    REPLACE ENGINE STOP AND START ECU Click here

    B

    USE SIMULATION METHOD TO CHECK Click here