SFI SYSTEM (w/ Electronic Throttle Control System) ECM Back-up Power Source Circuit

DESCRIPTION

The battery supplies electricity to terminal BATT of the ECM even when the ignition switch is OFF. This electricity allows the ECM to store DTC histories, freeze frame data, fuel trim values, and other data.

WIRING DIAGRAM

A013745E01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT FUSE (EFI FUSE)


    1. A0136TCE01

      Remove the EFI fuse from the engine room R/B.

    2. Measure the EFI fuse resistance.

      Standard resistance
      Below 1 Ω

    3. Reinstall the EFI fuse.


    NG

    CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE

    OK

  2. CHECK HARNESS AND CONNECTOR (EFI FUSE - ECM, EFI FUSE - BATTERY)


    1. A013877E03

      Disconnect the B25 ECM connector.

    2. Remove the engine room R/B.

    3. Remove the engine room R/B lower cover.

    4. Measure the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      BATT (B25-42) - Engine room R/B (1C-4) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      BATT (B25-42) or Engine room R/B (1C-4) - Body ground 10 kΩ or higher

    5. Reinstall the engine room R/B.

    6. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    CHECK AND REPLACE ENGINE ROOM RELAY BLOCK