STOP AND START SYSTEM, Diagnostic DTC:P1538

DTC Code DTC Name
P1538 Circuit Malfunction between AT Oil Pump and Stop and Start ECU

DESCRIPTION

The oil pump of the continuously variable transaxle assembly stops operating when the engine is stopped by stop and start control. While the engine is stopped by stop and start control, the oil pump with motor assembly is operated continuously ensuring optimal CVT oil pressure and smooth start-off when the engine is restarted.

The engine stop and start ECU supplies power to the oil pump with motor assembly via terminal OPO and operates the oil pump with motor assembly in accordance with signals sent from terminal OPM1. The oil pump with motor assembly sends operating speed signals to the engine stop and start ECU via the NOPM signal line.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory
P1538 Circuit Malfunction between AT Oil Pump and Stop and Start ECU

Both of the following conditions are met for 2 seconds or more (1 trip detection logic):


  • Oil pump motor relay circuit in the engine stop and start ECU is off

  • Oil pump with motor assembly power supply malfunction (Oil pump motor relay circuit in the engine stop and start ECU stuck on or shorted) or a short to ground in the NOPM circuit*1

Both of the following conditions are met for 1 second or more (2 trip detection logic):


  • Engine started

  • Oil pump with motor assembly circuit malfunction (Oil pump motor relay in the engine stop and start ECU stuck off, open or short to ground in the OPO, OPM1 or NOPM circuit or an open in the GND circuit)*2

  • Wire harness or connector

  • Oil pump with motor assembly

  • Engine stop and start ECU

 Blinks DTC stored

*1: "Abnormal" is displayed for the freeze frame data item [Status of O/P Signal 1]

*2: "Abnormal" is displayed for the freeze frame data item [Status of O/P Signal 2]

CONFIRMATION DRIVING PATTERN

Tech Tips

DTCs for the stop and start system are not cleared automatically 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 40 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 ignition switch to ON and turn the GTS on.

    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.

  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 40 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

A01T8DNE05
*a OPO
*b NOPM
*c Engine Stop and Start ECU
*d Oil Pump with Motor Assembly

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 with motor assembly after removing and installing the continuously variable transaxle assembly or replacing the CVT 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 FREEZE FRAME DATA

    Note

    The freeze frame data is cleared when DTCs are cleared. Be sure to make a note of necessary data in advance.


    1. According to the display on the GTS, select DTC P1538 and check the sets of freeze frame data.

      Click here

      Result
      Tester Display Result Proceed to
      Status of O/P Signal 1 Abnormal A
      Status of O/P Signal 2 Abnormal B

    B

    PERFORM ACTIVE TEST USING GTS (AT OIL PUMP (LO)) Click here

    A

  2. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - OIL PUMP WITH MOTOR ASSEMBLY)


    1. Disconnect the A8 and A9 engine stop and start ECU connectors.

    2. Disconnect the B210 oil pump with motor assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A9-27 (NOPM) - B210-3 (OPST) Always Below 1 Ω
      A8-6 (OPO) - B210-1 (+B) Always Below 1 Ω
      A9-27 (NOPM) - Body ground Always 10 kΩ or higher
      B210-3 (OPST) - Body ground Always 10 kΩ or higher
      A8-6 (OPO.) - Body ground Always 10 kΩ or higher
      B210-1 (+B) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ENGINE STOP AND START ECU (NOPM TERMINAL VOLTAGE)

    A01TA8UC13
    *a

    Component with harness connected

    (Engine Stop and Start ECU)

    		 - -

    1. Disconnect the B210 oil pump with motor assembly connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A9-27 (NOPM) - A8-8 (GND) Ignition switch ON 10 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE OIL PUMP WITH MOTOR ASSEMBLY Click here

    NG

    REPLACE ENGINE STOP AND START ECU Click here

  4. PERFORM ACTIVE TEST USING GTS (AT OIL PUMP (LO))


    1. Drive the vehicle to warm up the engine and CVT fluid.

      Tech Tips

      The oil pump with motor assembly may not operate properly if the CVT fluid temperature is low. Make sure to warm up the CVT fluid before performing the Active Test. (CVT fluid temperature: 30°C (86°F) or higher)

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

    6. Check the operating sound of the oil pump with motor assembly while performing the Active Test.

      Standard
      AT Oil Pump (Lo) Result
      ON Operating sound can be heard
      OFF Operating sound cannot be heard
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - OIL PUMP WITH MOTOR ASSEMBLY) Click here

    OK

  5. CHECK ENGINE STOP AND START ECU (NOPM TERMINAL WAVEFORM)


    1. Connect an oscilloscope to the A9-27 (NOPM) and A8-8 (GND) terminals of the engine stop and start ECU connector.

      A01TA8UC13
      *a

      Component with harness connected

      (Engine Stop and Start ECU)

      		 - -

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

    3. A01T9ESE03
      *a 5 V/DIV.
      *b 5 ms./DIV.

      Check the waveform while performing the Active Test.

      Item Condition
      Tester Connection A9-27 (NOPM) - A8-8 (GND)
      Tool Setting 5 V/DIV., 5 ms./DIV.
      Condition

      • Ignition switch ON (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
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

  6. CHECK OIL PUMP WITH MOTOR ASSEMBLY (OPST TERMINAL VOLTAGE)


    1. A01T9U1C04
      *a

      Front view of wire harness connector

      (to Oil Pump with Motor Assembly)

      Disconnect the B210 oil pump with motor assembly connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      B210-3 (OPST) - B210-4 (GND) Ignition switch ON 10 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE OIL PUMP WITH MOTOR ASSEMBLY Click here

    NG

  7. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - OIL PUMP WITH MOTOR ASSEMBLY)


    1. Disconnect the A9 engine stop and start ECU connector.

    2. Disconnect the B210 oil pump with motor assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A9-27 (NOPM) - B210-3 (OPST) Always Below 1 Ω
      A9-27 (NOPM) - Body ground Always 10 kΩ or higher
      B210-3 (OPST) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - OIL PUMP WITH MOTOR ASSEMBLY)


    1. Disconnect the A8 engine stop and start ECU connector.

    2. Disconnect the B210 oil pump with motor assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A8-6 (OPO) - B210-1 (+B) Always Below 1 Ω
      A8-6 (OPO) - Body ground Always 10 kΩ or higher
      B210-1 (+B) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (OIL PUMP WITH MOTOR ASSEMBLY - BODY GROUND)


    1. Disconnect the B210 oil pump with motor assembly connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      B210-4 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK ENGINE STOP AND START ECU (OPO TERMINAL VOLTAGE)

    A01TA8UC14
    *a

    Component with harness connected

    (Engine Stop and Start ECU)

    		 - -

    1. Disconnect the B210 oil pump with motor assembly connector.

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


      Powertrain > Stop and Start > Active Test
      Tester Display
      AT Oil Pump (Lo)

    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A8-6 (OPO) - A8-8 (GND)

      • Ignition switch ON (engine is stopped)

      • Active Test "AT Oil Pump (Lo)" being performed

      		 10 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ENGINE STOP AND START ECU Click here

    OK

  11. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - OIL PUMP WITH MOTOR ASSEMBLY)


    1. Disconnect the A9 engine stop and start ECU connector.

    2. Disconnect the B210 oil pump with motor assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A9-9 (OPM1) - B210-2 (SI) Always Below 1 Ω
      A9-9 (OPM1) - Body ground Always 10 kΩ or higher
      B210-2 (SI) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. CHECK OIL PUMP ASSEMBLY WITH MOTOR (OPM1 TERMINAL WAVEFORM)


    1. Connect an oscilloscope to the A9-9 (OPM1) and A8-8 (GND) terminals of the engine stop and start ECU connector.

      A01TA8UC15
      *a

      Component with harness connected

      (Engine Stop and Start ECU)

      		 - -

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


      Powertrain > Stop and Start > Active Test
      Tester Display
      AT Oil Pump (Lo)
    6. A01TA9UE01
      *a 5 V/DIV.
      *b 5 ms./DIV.

      Check the waveform while performing the Active Test.

      Item Condition
      Tester Connection A9-9 (OPM1) - A8-8 (GND)
      Tool Setting 5 V/DIV., 5 ms./DIV.
      Condition

      • Ignition switch ON (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
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPLACE OIL PUMP WITH MOTOR ASSEMBLY Click here