SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the engine switch is turned on (IG), 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 EFI MAIN relay and supplying power to terminal +B and +B2 of the ECM.

If the engine switch is turned off, the ECM holds the EFI MAIN relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

When the engine switch is turned on (IG), voltage from the ECM's MREL terminal is applied to the EFI MAIN relay. This causes the contacts of the EFI MAIN relay to close, which supplies power to terminal +B and +B2 of the ECM.

WIRING DIAGRAM

A0161XGE01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECM (+B, +B2 VOLTAGE)


    1. A015Z7TE90

      Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A6-2 (+B) - E6-1 (E1) Engine switch on (IG) 11 to 14 V
      A6-1 (+B2) - E6-1 (E1) Engine switch on (IG) 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Click here

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Click here

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


    1. A0160VUE08

      Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      E6-1 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (IGSW VOLTAGE)


    1. A015Z7TE91

      Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A5-8 (IGSW) - E6-1 (E1) Engine switch on (IG) 11 to 14 V

    NG

    CHECK FUSE (IGN FUSE) Click here

    OK

  4. INSPECT ECM (MREL VOLTAGE)


    1. A015Z7TE92

      Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A5-3 (MREL) - E6-1 (E1) Engine switch on (IG) 11 to 14 V

    NG

    REPLACE ECM Click here

    OK

  5. CHECK FUSE (EFI FUSE)


    1. A015YXDE03

      Remove the EFI fuse from the engine room No. 2 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      EFI fuse Always Below 1 Ω

    3. Reinstall the EFI fuse.


    NG

    CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE (EFI FUSE)

    OK

  6. INSPECT INTEGRATION RELAY (EFI MAIN RELAY)


    1. A015ZGTE06

      Remove the integration relay from the engine room No. 2 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2C-1 - 2A-8 When no battery voltage applied terminals 2A-6 and 2A-7 10 kΩ or higher
      When battery voltage applied to terminals 2A-6 and 2A-7 Below 1 Ω

    3. Reinstall the integration relay.


    NG

    REPLACE INTEGRATION RELAY Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM AND BODY GROUND)


    1. A016376E03

      Remove the integration relay from the engine room No. 2 relay block.

    2. Disconnect the ECM connector.

    3. Check the harness and the connectors between the integration relay and the ECM.


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

        Standard Resistance (Check for Open)
        Tester Connection Condition Specified Condition
        2A-6 - A5-3 (MREL) Always Below 1 Ω
        Standard Resistance (Check for Short)
        Tester Connection Condition Specified Condition
        2A-6 or A5-3 (MREL) - Body ground Always 10 kΩ or higher

    4. Check the harness and the connectors between the integration relay and body ground.


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

        Standard Resistance (Check for Open)
        Tester Connection Condition Specified condition
        2A-7 - Body ground Always Below 1 Ω

    5. Reinstall the integration relay to the engine room No. 2 relay block.

    6. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM)


    1. A0161SSE02

      Remove the integration relay from the engine room No. 2 relay block.

    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
      2A-8 - A6-2 (+B) Always Below 1 Ω
      2A-8 - A6-1 (+B2) Always Below 1 Ω

    4. Reinstall the integration relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI RELAY - ECM)

    OK

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

  9. CHECK FUSE (IGN FUSE)


    1. A0160WDE03

      Remove the IGN fuse from the cowl side junction block RH.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      IGN fuse Always Below 1 Ω

    3. Reinstall the fuse.


    NG

    CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE

    OK

  10. INSPECT IG2 RELAY


    1. A0161LXE03

      Remove the IG2 relay from the engine room No. 2 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 When no battery voltage applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 When battery voltage applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the relay.


    NG

    REPLACE IG2 RELAY

    OK

  11. CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY)


    1. A0162GWE01

      Remove the IG2 relay from the engine room No. 2 relay block.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      IG2 relay (3) - A5-8 (IGSW) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      IG2 relay (3) or A5-8 (IGSW) Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. CHECK FUSE (IG2 MAIN FUSE)


    1. A0160G5E02

      Remove the IG2 MAIN fuse the engine room No. 1 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      IG2 MAIN fuse Always Below 1 Ω

    3. Reinstall the IG2 MAIN fuse.


    NG

    CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE (IG2 MAIN FUSE)

    OK

  13. CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE CIRCUIT)


    1. A0161A7E01

      Remove the IG2 relay from the engine room No. 2 relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      IG2 relay (5) - Body ground Always 11 to 14 V

    3. Reinstall the IG2 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY)

    OK

    GO TO ENTRY AND START SYSTEM Click here