STOP AND START SYSTEM, Diagnostic DTC:P0942

DTC Code DTC Name
P0942 Hydraulic Pressure Unit

DESCRIPTION

Refer to DTC P1538 Click here

DTC No. DTC Detection Condition Trouble Area
P0942

The following conditi9on continues for 0.5 seconds or more (2 trip detection logic):


  • Difference between turbine speed and output shaft speed is 120 rpm or more after engine restarted during idling stop when shift lever is in D.

  • Oil pump assembly with motor (automatic transaxle assembly)

  • Engine stop and start ECU

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 Click here.


  1. CONFIRMATION AFTER TROUBLESHOOTING

    Tech Tips


    • If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 60 minutes until refresh charge is completed and stop and start control operation is permitted.

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


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG) and turn the GTS on Click here.

    3. Clear the 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 Click here.

  2. STOP AND START SYSTEM OPERATION CHECK

    Tech Tips

    If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 60 minutes until refresh charge is completed and stop and start control operation is permitted.


    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

Refer to DTC P1538 Click here.

CAUTION / NOTICE / HINT

Note


  • Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU Click here.

  • After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU Click here.

  • After replacing the engine stop and start ECU or airbag sensor assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU Click here.

  • Bleed the oil pump assembly with motor (automatic transaxle assembly) after removing and installing the automatic transaxle assembly or replacing the automatic transaxle fluid Click here.

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 Click here.

PROCEDURE


  1. CHECK WAVEFORM (NOPM TERMINAL WAVEFORM)


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

      Note

      The oil pump assembly with motor (automatic transaxle 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. Connect the GTS to the DLC3.

    3. Turn the engine switch on (IG).

      Tech Tips

      Do not start the engine.

    4. Turn the GTS on.

    5. Connect an oscilloscope to terminals A77-27 (NOPM) and A77-6 (DGND).

      A01VZQXE02
      Text In Illustration
      *a

      Component with harness connected

      (Engine stop and start ECU)

      		 - -

    6. Enter the following menus: Powertrain / Stop and Start / Active Test / AT Oil Pump (Lo).

    7. A01VZVSE09
      *a 5 V/DIV.
      *b 5 ms./DIV.

      Check the waveform while performing the Active Test.

      Item Condition
      Tester Connection A77-27 (NOPM) - A77-6 (DGND)
      Tool Setting 5 V/DIV., 5 ms./DIV.
      Condition

      • Turn the engine switch on (IG) (engine is stopped)

      • Active Test "AT Oil Pump (Lo)" being performed
      Standard
      The waveform is similar to that shown in the illustration with no noise.
      Result
      Result Proceed to

      17 to 200 Hz

      (Normal Waveform)

      		 A

      Except 17 to 200 Hz

      (Abnormal Waveform)

      		 B

      Tech Tips


      • 17 Hz: Period is 59 ms (oil pump with motor assembly (automatic transaxle assembly) speed is approximately 510 rpm).

      • 200 Hz: Period is 5 ms (oil pump with motor assembly (automatic transaxle assembly) speed is approximately 6000 rpm).

      • The higher the oil pump with motor assembly (automatic transaxle assembly) speed becomes, the shorter the wavelength.


    B

    REPLACE OIL PUMP ASSEMBLY WITH MOTOR (AUTOMATIC TRANSAXLE ASSEMBLY) Click here

    A

  2. CLEAR DTC


    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 / Stop and Start / Trouble Codes.

    5. Clear the DTCs.


    NEXT

  3. CHECK DTC OUTPUT


    1. Start the engine.

    2. Perform a rood test

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

    4. Read the DTCs.

      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