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 integration relay (EFI MAIN1 relay) and supplying power to terminal +B and +B2 of the ECM.

If the engine switch is turned off, the ECM holds the integration relay (EFI MAIN1 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 integration relay (EFI MAIN1 relay). This causes the contacts of the integration relay (EFI MAIN1 relay) to close, which supplies power to terminal +B and +B2 of the ECM.

WIRING DIAGRAM

A01FENXE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


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


    1. A01FGK3E34
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      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
      A21-2 (+B) - F4-1 (E1) Engine switch on (IG) 11 to 14 V
      A21-1 (+B2) - F4-1 (E1) Engine switch on (IG) 11 to 14 V

    NG

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

    OK

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

  2. 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
      F4-1 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

    OK

  3. INSPECT ECM (IGSW VOLTAGE)


    1. A01FGK3E35
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      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
      A19-8 (IGSW) - F4-1 (E1) Engine switch on (IG) 11 to 14 V

    NG

    INSPECT NO. 1 INTEGRATION RELAY (IG2 RELAY) Click here

    OK

  4. INSPECT ECM (MREL VOLTAGE)


    1. A01FGK3E36
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      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
      A19-3 (MREL) - F4-1 (E1) Engine switch on (IG) 11 to 14 V

    NG

    REPLACE ECM Click here

    OK

  5. INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN1 RELAY)


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


    NG

    REPLACE NO. 1 INTEGRATION RELAY

    OK

  6. CHECK HARNESS AND CONNECTOR (EFI MAIN1 RELAY - ECM)


    1. Remove the No. 1 integration relay from the No. 2 engine room 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
      2E-6 - A19-3 (MREL) Always Below 1 Ω
      2E-6 or A19-3 (MREL) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the No. 1 integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN1 RELAY - ECM)

    OK

  7. CHECK HARNESS AND CONNECTOR (EFI MAIN1 RELAY - ECM)


    1. Remove the No. 1 integration relay from the engine room No. 2 relay 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
      2F-9 - A21-2 (+B) Always Below 1 Ω
      2F-10 - A21-1 (+B2) Always Below 1 Ω
      2F-9 or A21-2 (+B) - Body ground Always 10 kΩ or higher
      2F-10 or A21-1 (+B2) - Body ground Always 10 kΩ or higher

    4. Reinstall the No. 1 integration relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN1 RELAY - ECM)

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - NO. 1 INTEGRATION RELAY)

  8. INSPECT NO. 1 INTEGRATION RELAY (IG2 RELAY)


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


    NG

    REPLACE NO. 1 INTEGRATION RELAY

    OK

  9. CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY, BODY GROUND)


    1. Check the harness and the connectors between the No. 1 integration relay and the ECM.


      1. Remove the No. 1 integration relay from the No. 2 engine room relay 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
        2F-6 - A19-8 (IGSW) Always Below 1 Ω
        2F-6 or A19-8 (IGSW) - Body ground Always 10 kΩ or higher

      4. Reconnect the ECM connector.

    2. Check the harness and the connectors between the No. 2 engine room relay block assembly and body ground.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        2F-1 - Body ground Always Below 1 Ω

      2. Reinstall the No. 1 integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - IG2 RELAY, BODY GROUND)

    OK

  10. CHECK NO. 1 INTEGRATION RELAY (POWER SOURCE)


    1. A01FHEYE02
      Text in Illustration
      *a

      Front view of wire harness connector

      to No. 1 Integration Relay

      Remove the No. 1 integration relay from the No. 2 engine room relay block assembly.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      2D-1 - Body ground Always 11 to 14 V

    3. Reinstall the No. 1 integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START Click here