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

A01BFEIE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. INSPECT ECM (+B VOLTAGE)


    1. A01BBFDE01
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B9-1 (+B) - D1-3 (E1) Ignition switch ON 11 to 14 V

    NG

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

    OK

    GO TO PROBLEM SYMPTOMS TABLE

  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 (Check for open)
      Tester Connection Condition Specified Condition
      D1-3 (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. A01BBFDE02
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B9-9 (IGSW) - D1-3 (E1) Ignition switch ON 11 to 14 V

    NG

    INSPECT IGNITION SWITCH Click here

    OK

  4. INSPECT ECM (MREL VOLTAGE)


    1. A01BBFDE03
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      B9-8 (MREL) - D1-3 (E1) Ignition switch ON 11 to 14 V

    NG

    REPLACE ECM

    OK

  5. INSPECT INTEGRATION RELAY (MAIN RELAY)


    1. Inspect the integration relay (MAIN relay) Click here.


    NG

    REPLACE INTEGRATION RELAY

    OK

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


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

    2. Disconnect the ECM connector.

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

      Resistance (Check for open)
      Tester Connection Condition Specified Condition
      1J-4 - B9-1 (+B) Always Below 1 Ω
      1J-2 - B9-8 (MREL) Always Below 1 Ω
      1J-3 - Body ground Always Below 1 Ω
      Resistance (Check for short)
      Tester Connection Condition Specified condition
      1J-4 or B9-1 (+B) - Body ground Always 10 kΩ or higher
      1J-2 or B9-8 (MREL) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

  7. INSPECT IGNITION SWITCH


    1. Inspect the ignition switch Click here.


    NG

    REPLACE IGNITION SWITCH

    OK

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