SFI SYSTEM ECM Back-up Power Source Circuit

DESCRIPTION

While the ignition switch is OFF, battery voltage is supplied to terminal BATT of the ECM for the DTC memory, air-fuel ratio adaptive control value memory, etc.

WIRING DIAGRAM

A01DZUYE01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT FUSE (EFI)

    A01E0XOE06

    1. Remove the EFI fuse from the engine room junction block.

    2. Measure the resistance of the fuse.

      Standard resistance
      Below 1 Ω

    NG

    CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE

    OK

  2. CHECK ECM (BATT VOLTAGE)

    A01DYCSE25

    1. Turn the ignition switch ON.

    2. Measure the voltage of the ECM connectors.

      Standard voltage
      Tester Connection Specified Condition
      E9-3 (BATT) - E12-3 (E1) 8 to 14 V

    OK

    REPLACE ECM

    NG

  3. CHECK WIRE HARNESS (ECM - EFI FUSE, EFI FUSE - BATTERY)

    A01E0EKE03

    1. Check the wire harness between the EFI fuse and ECM.


      1. Remove the EFI fuse from the engine room junction block.

      2. Disconnect the E9 ECM connector.

      3. Measure the resistance of the wire harness side connectors.

        Standard resistance
        Tester Connection Specified Condition
        J/B EFI fuse terminal 2 - E9-3 (BATT) Below 1 Ω
        J/B EFI fuse terminal 2 or E9-3 (BATT) - Body ground 10 kΩ or higher

    2. Check the wire harness between the EFI fuse and battery.


      1. Remove the EFI fuse from the engine room junction block.

      2. Disconnect the positive (+) battery cable.

      3. Measure the resistance of the wire harness side connectors.

        Standard resistance
        Tester Connection Specified Condition
        Positive (+) battery cable - J/B EFI fuse terminal 1 Below 1 Ω

        Positive (+) battery cable or J/B EFI fuse terminal 1 -

        Body ground

        		 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE ENGINE ROOM RELAY BLOCK