STOP AND START SYSTEM Starter Inrush Current Reduction Relay Circuit

DESCRIPTION

The starter inrush current reduction relay prevents the battery voltage from becoming dropping excessively while the starter assembly is operating. If the battery voltage drops below the threshold, stop and start control will be prohibited. In order to prevent this, the engine stop and start ECU operates the starter inrush current reduction relay for approximately 0.1 seconds after the ST NO. 2 relay is activated. By allowing current to flow to the starter inrush current reduction relay, the current that flows to the starter motor is reduced, preventing the battery voltage from dropping excessively.

B00579EE06

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

Tech Tips


  • Starter inrush current reduction relay stuck on:

    When the engine is started by stop and start control, a large amount of current will flow to the starter assembly, the battery voltage will drop excessively and stop and start control will be canceled.

  • Starter inrush current reduction relay stuck off:

    Operating current will always flow through the starter inrush current reduction relay and the cranking speed will be low.

PROCEDURE


  1. CHECK WAVEFORM (STARTER INRUSH CURRENT REDUCTION RELAY)


    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 / Active Test / Starter Motor Drive Magnet Switch / Data List / Min Volt(After Cranking).

    5. Select the Data List item "Min Volt(After Cranking)".


      Powertrain > Stop and Start > Active Test
      Active Test Display
      Starter Motor Drive Magnet Switch
      Data List Display
      Min Volt(After Cranking)

    6. Connect the positive (+) lead of an oscilloscope to the positive (+) battery terminal and the negative (-) lead to the negative (-) battery terminal.

    7. While performing the Active Test "Starter Motor Drive Magnet Switch" to forcibly operate the starter motor, count the number of times the waveform drops and check the Data List item "Min Volt(After Cranking)".

      Note


      • The Active Test "Starter Motor Drive Magnet Switch" is stopped automatically after the starter motor operates for 3 seconds.

      • Do not forcibly operate the starter pinion.

      B0057UZE02
      Standard
      Specified battery
      for 8AR-FTS: The voltage waveform has 2 peaks and the "Min Volt (After Cranking)" Data List item (the minimum voltage after the starter begins operation) is 8.08 V or higher
      for 3ZR-FAE: The voltage waveform has 2 peaks and the "Min Volt (After Cranking)" Data List item (the minimum voltage after the starter begins operation) is 7.66 V or higher
      Non-specified battery
      The voltage waveform has 2 peaks and the "Min Volt (After Cranking)" Data List item (the minimum voltage after the starter begins operation) is 8.92 V or higher
      Result
      Number of Times Waveform Dropped Min Volt(After Cranking) (Data List Item) Proceed to
      2 times

      for 8AR-FTS: 8.08 V or higher*1, 8.92 V or higher*2

      for 3ZR-FAE: 7.66 V or higher*1, 8.92 V or higher*2

      		 A
      2 times

      for 8AR-FTS: Below 8.08 V*1, Below 8.92 V*2

      for 3ZR-FAE: Below 7.66 V*1, Below 8.92 V*2

      		 B
      Less than 2 times

      for 8AR-FTS: 8.08 V or higher*1, 8.92 V or higher*2

      for 3ZR-FAE: 7.66 V or higher*1, 8.92 V or higher*2

      		 C
      Less than 2 times

      for 8AR-FTS: Below 8.08 V*1, Below 8.92 V*2

      for 3ZR-FAE: Below 7.66 V*1, Below 8.92 V*2

      		 D

      • *1: Specified battery

      • *2: Non-specified battery


    B

    CHECK BATTERY for 8AR-FTS: Click here for 3ZR-FAE: Click here

    C

    REPLACE STARTER INRUSH CURRENT REDUCTION RELAY for 8AR-FTS: Click here for 3ZR-FAE: Click here

    D

    REPLACE AND CHECK BATTERY

    A

  2. CHECK WAVEFORM (BATTERY VOLTAGE WHEN STARTER ASSEMBLY OPERATED)


    1. Enter the following menus: Powertrain / Stop and Start / Active Test / Starter Motor Drive Magnet Switch.

    2. Connect the positive (+) lead of an oscilloscope to the positive (+) battery terminal and the negative (-) lead to the negative (-) battery terminal. Also connect the oscilloscope to terminals A38-21 (STA) and A37-8 (GND) of the stop and start ECU.

      B0057SGC81
      *a

      Component with harness connected

      (Engine Stop and Start ECU)

      		 - -

    3. While performing the Active Test "Starter Motor Drive Magnet Switch" to forcibly operate the starter motor, measure the battery voltage.

      Note

      The Active Test "Starter Motor Drive Magnet Switch" is stopped automatically after the starter motor operates for 3 seconds.

      B005AZXE05
      Standard
      Specified battery
      for 8AR-FTS: The minimum voltage immediately after cranking is 8.08 V or higher and the voltage approximately 0.03 seconds after the ST relay is turned ON is approximately 8.14 V or higher
      for 3ZR-FAE: The minimum voltage immediately after cranking is 7.66 V or higher and the voltage approximately 0.03 seconds after the ST relay is turned ON is approximately 8.14 V or higher
      Non-specified battery
      The minimum voltage immediately after cranking is 8.92 V or higher and the voltage approximately 0.03 seconds after the ST relay is turned ON is approximately 8.92 V or higher

      Tech Tips

      Check the value of the following Data List items at the same time.


      • for 8AR-FTS:

        Data List [Min Voltage(Cranking)]: 8.08 V or higher*1, 8.92 V or higher*2

        for 3ZR-FAE:

        Data List [Min Voltage(Cranking)]: 7.66 V or higher*1, 8.92 V or higher*2

      • Data List [Min Volt(After Cranking)]: 8.14 V or higher*1, 8.92 V or higher*2


      • *1: Specified battery

      • *2: Non-specified battery

      Result
      Proceed to
      OK
      NG

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

    CHECK BATTERY for 8AR-FTS: Click here for 3ZR-FAE: Click here