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СИСТЕМА ECD ECM Power Source Circuit

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DTC Code DTC Name
  ECM Power Source Circuit
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DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to terminal IGSW of the ECM. The MREL output signal from ECM causes a current to flow to the coil, closing the contacts of the EFI MAIN relay and supplying power to terminal +B of the ECM.

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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

  • After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).

  • Inspect the fuses of circuits related to this system before performing the following inspection procedure.

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. Disconnect the ECM connector.

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

      Standard Resistance:
      Tester Connection Condition Specified Condition
      D105-109 (E1) - Body ground Always Below 1 Ω

  2. Click here

    CHECK TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE)


    1. A003EHPE25

      Disconnect the ECM 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
      B88-25 (IGSW) - Body ground Ignition switch ON 11 to 14 V
      Table 1. Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

  3. Click here

    INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN RELAY)


    1. Inspect the No. 1 integration relay (EFI MAIN relay) (Click here).


  4. Click here

    CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM, EFI MAIN RELAY - BODY GROUND)


    1. Check the harness and connector between the No. 1 integration relay (EFI MAIN relay) and ECM.


      1. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block assembly.

      2. Disconnect the ECM connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        10B-4 - B88-1 (+B) Always Below 1 Ω
        10B-2 - B88-28 (MREL) Always Below 1 Ω
        10B-4 or B88-1 (+B) - Body ground Always 10 kΩ or higher
        10B-2 or B88-28 (MREL) - Body ground Always 10 kΩ or higher

      4. Reconnect the ECM connector.

      5. Reinstall the No. 1 integration relay.

    2. Check the harness and connector between the No. 1 integration relay (EFI MAIN relay) and body ground.


      1. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block assembly.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        10B-3 - Body ground Always Below 1 Ω

      3. Reinstall the No. 1 integration relay.


  5. Click here

    INSPECT IGNITION SWITCH


    1. Inspect the ignition switch (Click here).


  6. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. Click here

    REPLACE INTEGRATION NO. 1 RELAY (EFI MAIN RELAY)

  8. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - MAIN RELAY)

  9. Click here

    REPLACE IGNITION SWITCHClick here

  10. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION SWITCH, IGNITION SWITCH - ECM)