SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the power switch is turned on (IG), auxiliary battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the No. 2 integration relay (EFI MAIN relay) and supplying power to either terminal +B and +B2 of the ECM.

WIRING DIAGRAM

A0041U4E06

INSPECTION PROCEDURE

Note


  • After turning power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary 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 - 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
      D28-104 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. INSPECT ECM (IGSW VOLTAGE)


    1. A0041URE86
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A56-28 (IGSW) - Body ground Power switch on (IG) 11 to 14 V

    NG

    INSPECT NO. 2 INTEGRATION RELAY (IG2 RELAY) Click here

    OK

  3. INSPECT NO. 2 INTEGRATION RELAY (EFI MAIN RELAY)


    1. Inspect the No. 2 integration relay (EFI MAIN relay) Click here.


    NG

    REPLACE NO. 2 INTEGRATION RELAY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (EFI MAIN RELAY) - ECM)


    1. Remove the No. 2 integration relay (EFI MAIN relay) from the engine room relay block and junction 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
      1B-4 - A57-1 (+B2) Always Below 1 Ω
      1B-4 - A57-2 (+B) Always Below 1 Ω
      1B-2 - A57-6 (MREL) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (EFI MAIN RELAY) - BODY GROUND)


    1. Remove the No. 2 integration relay (EFI MAIN relay) from the engine room relay block and junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1B-3 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

  6. INSPECT NO. 2 INTEGRATION RELAY (IG2 RELAY)


    1. Inspect the No. 2 integration relay (IG2 relay) Click here.


    NG

    REPLACE NO. 2 INTEGRATION RELAY Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (IG2 RELAY) - ECM)


    1. Disconnect the ECM connector.

    2. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block and junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1A-4 - A57-28 (IGSW) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (IG2 RELAY) - AUXILIARY BATTERY)


    1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block and junction block assembly.

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

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1C-1 - Positive (+) auxiliary battery terminal Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (IG2 RELAY) - BODY GROUND)


    1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block and junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1A-3 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - NO. 2 INTEGRATION RELAY)


    1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block and junction block assembly.

    2. Disconnect the power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A21-2 (IG2D) - 1A-2 Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    CHECK ENTRY AND START SYSTEM (FOR START FUNCTION) Click here