SFI SYSTEM (w/o Secondary Air Injection 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

A003E2DE07

INSPECTION PROCEDURE

Note


  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Click here.

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

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (ECM - BATTERY)


    1. Disconnect the ECM connector.

    2. Disconnect the cable from the negative (-) battery terminal.

    3. Disconnect the cable from the positive (+) battery terminal.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B71-20 (BATT) - Positive (+) battery cable terminal Always Below 1 Ω
      B71-20 (BATT) or positive (+) battery cable terminal - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT BATTERY


    1. Check that the battery is not depleted Click here.

      OK
      Battery is not depleted.

    NG

    REPLACE BATTERY

    OK

  3. CHECK BATTERY TERMINAL


    1. Check that the battery terminals are not loose or corroded.

      OK
      Battery terminals are not loose or corroded.

    NG

    REPAIR BATTERY TERMINAL

    OK

  4. CHECK ECM (BATT VOLTAGE)


    1. A003HG9E17
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      B71-20 (BATT) - Body ground Always 11 to 14 V

    NG

    PERFORM SIMULATION TEST Click here

    OK

    REPLACE ECM Click here