SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the engine switch is turned on (IG), the battery voltage is applied to the IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the No. 2 integration relay (EFI MAIN NO. 1 relay) and supplying power to either terminal +B or +B2 of the ECM.

WIRING DIAGRAM



CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. INSPECT NO. 2 INTEGRATION RELAY (POWER SOURCE)


    1. B001AD5E04
      *1 Front view of wire harness connector: (to No. 2 integration relay)

      Disconnect the No. 2 integration relay connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      1M-1 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - NO. 2 INTEGRATION RELAY)

    OK

  2. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - BODY GROUND)


    1. Disconnect the No. 2 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1Q-4 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT NO. 2 INTEGRATION RELAY (IG2 MAIN, EFI MAIN NO. 1)


    1. Inspect the No. 2 integration relay Click here.


    NG

    REPLACE NO. 2 INTEGRATION RELAY

    OK

  4. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - ECM)


    1. Disconnect the ECM connector.

    2. Disconnect the No. 2 integration relay connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A38-6 (MREL) - 1Q-8 Always Below 1 Ω
      A38-2 (+B) - 1Q-11 Always Below 1 Ω
      A38-3 (+B2) - 1Q-11 Always Below 1 Ω
      A38-6 (MREL) or 1Q-8 - Body ground Always 10 kΩ or higher
      A38-2 (+B) or 1Q-11 - Body ground Always 10 kΩ or higher
      A38-3 (+B2) or 1Q-11 - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      A87-6 (MREL) - 1Q-8 Always Below 1 Ω
      A87-2 (+B) - 1Q-11 Always Below 1 Ω
      A87-3 (+B2) - 1Q-11 Always Below 1 Ω
      A87-6 (MREL) or 1Q-8 - Body ground Always 10 kΩ or higher
      A87-2 (+B) or 1Q-11 - Body ground Always 10 kΩ or higher
      A87-3 (+B2) or 1Q-11 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. 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
      for LHD
      Tester Connection Condition Specified Condition
      C53-81 (E1) - Body ground Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      C54-81 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT ECM (IGSW VOLTAGE)


    1. B001AORE03

      Disconnect the ECM connectors.

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      for LHD
      Tester Connection Switch Condition Specified Condition
      A38-4 (IGSW) - Body ground Engine switch on (IG) 11 to 14 V
      for RHD
      Tester Connection Switch Condition Specified Condition
      A87-4 (IGSW) - Body ground Engine switch on (IG) 11 to 14 V

    OK

    REPLACE ECM Click here

    NG

  7. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - ECM)


    1. Disconnect the ECM connector.

    2. Disconnect the No. 2 integration relay connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A38-4 (IGSW) - 1N-7 Always Below 1 Ω
      A38-4 (IGSW) or 1N-7 - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      A87-4 (IGSW) - 1N-7 Always Below 1 Ω
      A87-4 (IGSW) or 1N-7 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (SMART KEY ECU ASSEMBLY - NO. 2 INTEGRATION RELAY)


    1. Disconnect the smart key ECU assembly connector.

    2. Disconnect the No. 2 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E149-3 (IG1D) - 1P-2 Always Below 1 Ω
      E149-3 (IG1D) or 1P-2 - Body ground Always 10 kΩ or higher

    OK

    CHECK ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR