SFI SYSTEM (w/o Secondary Air Injection System) ECM Power Source Circuit

DESCRIPTION

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

WIRING DIAGRAM

A01BAIME01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECM (+B VOLTAGE)


    1. A01BDNSE28

      Turn the ignition switch to the ON position.

    2. Measure the voltage between the terminals of the ECM connectors.

      Voltage
      Tester Connections Specified Conditions
      +B (B9-1) - E1 (D1-3) 9 to 14 V

    OK

    GO TO PROBLEM SYMPTOMS TABLE

    NG

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. A01BC59E20

      Disconnect the negative battery cable.

    2. Disconnect the D1 ECM connector.

    3. Measure the resistance.

      Resistance (Check for open)
      Tester Connections Specified Conditions
      E1 (D1-3) - Body ground Below 1 Ω

    4. Reconnect the ECM connector.

    5. Reconnect the negative battery cable.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (IGSW VOLTAGE)


    1. A01BDNSE29

      Turn the ignition switch to the ON position.

    2. Measure the voltage between the terminals of the ECM connectors.

      Voltage
      Tester Connections Specified Conditions
      IGSW (B9-9) - E1 (D1-3) 9 to 14 V

    OK

    INSPECT ECM (MREL VOLTAGE) Click here

    NG

  4. CHECK AM2 OR IGN FUSE


    1. A01BHOVE01

      Check the AM2 fuse.


      1. Remove the AM2 fuse from the engine room R/B No.2.

      2. Measure the AM2 fuse resistance.

        Resistance
        Below 1 Ω

      3. Reinstall the AM2 fuse.

    2. Check the IGN fuse.


      1. Remove the IGN fuse from the instrument panel J/B.

      2. Measure the IGN fuse resistance.

        Resistance
        Below 1 Ω

      3. Reinstall the IGN fuse.


    NG

    REPLACE AM2 OR IGN FUSE

    OK

  5. INSPECT IGNITION SWITCH


    1. A01BDSUE01

      Disconnect the I7 ignition switch connector.

    2. Measure the resistance.

      Resistance
      Ignition Switch Positions Tester Connections Specified Conditions
      LOCK All Terminals 10 kΩ or higher
      ACC 2 - 3 Below 1 Ω
      ON 2 - 3, 2 - 4, 6 - 7 Below 1 Ω
      START 2 - 3, 6 - 7, 1 - 2, 7 - 8 Below 1 Ω

    3. Reconnect the ignition switch connector.


    NG

    REPLACE IGNITION SWITCH

    OK

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

  6. INSPECT ECM (MREL VOLTAGE)


    1. A01BDNSE30

      Turn the ignition switch to the ON position.

    2. Measure the voltage between the terminals of the ECM connectors.

      Voltage
      Tester Connector Specified Condition
      MREL (B9-8) - E1 (D1-3) 9 to 14 V

    NG

    REPLACE ECM

    OK

  7. CHECK EFI FUSE


    1. A01BFWGE01

      Remove the EFI fuse from the engine room R/B No.1.

    2. Measure the EFI fuse resistance.

      Resistance
      Below 1 Ω

    3. Reinstall the EFI fuse.


    NG

    REPLACE EFI FUSE

    OK

  8. INSPECT INTEGRATION NO.1 RELAY (EFI RELAY)


    1. Remove the integration relay from the engine room R/B No.1.

    2. A01BH79E01

      Measure the integration relay (MAIN relay) resistance.

      Resistance
      Tester Connections Specified Conditions
      A1 - B4 10 kΩ or higher
      A1 - B4

      Below 1 Ω

      (when battery voltage applied to terminals B2 and B3)

    3. Reinstall the integration relay.


    NG

    REPLACE INTEGRATION NO.1 RELAY

    OK

  9. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, INTEGRATION RELAY - BODY GROUND)


    1. A01BHB6E01

      Check the harness and connector between the integration relay and the ECM.


      1. Remove the Integration relay from the engine room R/B No.1.

      2. Disconnect the B9 ECM connector.

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

        Resistance (Check for open)
        Tester Connection Specified Condition
        Integration relay (B2) - MREL (B9-8) Below 1 Ω
        Resistance (Check for short)
        Tester Connection Specified Condition

        Integration relay (B2) or MREL (B9-8)

        - Body ground

        		 10 kΩ or higher

    2. Check the harness and connector between the integration relay and the body ground.


      1. Remove the integration relay from the engine room R/B No.1.

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

        Resistance (Check for open)
        Tester Connection Specified Condition
        Integration relay (B3) - Body ground Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - BATTERY POSITIVE TERMINAL)