SFI SYSTEM (w/o EGR System) ECM Power Source Circuit

DESCRIPTION

When the power switch is turned on (IG), the 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 contact of the EFI MAIN relay and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM

A01NGAEE02

INSPECTION PROCEDURE

Note

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
      D1-46 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

    OK

  2. INSPECT ECM (IGSW VOLTAGE)


    1. A01NEJ1E09
      Text in Illustration
      *1

      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 Switch Condition Specified Condition
      A76-1 (IGSW) - Body ground Power switch on (IG) 11 to 14 V

    4. Reconnect the ECM connector.


    NG

    INSPECT RELAY (IG2 RELAY) Click here

    OK

  3. INSPECT RELAY (EFI MAIN RELAY)


    1. A01ND26E03

      Remove the EFI MAIN relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 No battery voltage applied to terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the EFI MAIN relay relay.


    NG

    REPLACE RELAY (EFI MAIN RELAY)

    OK

  4. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM)


    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
      3 (EFI MAIN relay terminal) - A76-3 (+B) Always Below 1 Ω
      3 (EFI MAIN relay terminal) - A76-4 (+B2) Always Below 1 Ω
      1 (EFI MAIN relay terminal) - A76-21 (MREL) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      3 (EFI MAIN relay terminal) or A76-3 (+B) - Body ground Always 10 kΩ or higher
      3 (EFI MAIN relay terminal) or A76-4 (+B2) - Body ground Always 10 kΩ or higher
      1 (EFI MAIN relay terminal) or A76-21 (MREL) - Body ground Always 10 kΩ or higher

    3. Reconnect the ECM connector.

    4. Reinstall the EFI MAIN relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - ECM)

    OK

  5. CHECK HARNESS AND CONNECTOR (BATTERY - EFI MAIN RELAY)


    1. Remove the EFI MAIN relay from the engine room relay block.

    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 (Check for Open)
      Tester Connection Condition Specified Condition
      5 (EFI MAIN relay terminal) - Battery positive (+) terminal Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      5 (EFI MAIN relay terminal) - Body ground Always 10 kΩ or higher

    5. Reinstall the EFI MAIN relay.

    6. Reconnect the cable to the positive (+) battery terminal.

    7. Reconnect the cable to the negative (-) battery terminal.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI MAIN RELAY)

    OK

  6. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - BODY GROUND)


    1. Remove the EFI MAIN relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2 (EFI MAIN relay terminal) - Body ground Always Below 1 Ω

    3. Reinstall the EFI MAIN relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - BODY GROUND)

    OK

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

  7. INSPECT RELAY (IG2 RELAY)


    1. A01ND26E46

      Remove the IG2 relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 No battery voltage applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the IG2 relay.


    NG

    REPLACE RELAY (IG2 RELAY)

    OK

  8. CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM)


    1. Remove the IG2 relay from the engine room relay block.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      3 (IG2 relay terminal) - A76-1 (IGSW) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      3 (IG2 relay terminal) or A76-1 (IGSW) - Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - ECM)

    OK

  9. CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE)


    1. A01NDCTE01
      Text in Illustration
      *1 Engine Room Relay Block

      Remove the IG2 relay from the engine room relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      5 (IG2 relay terminal) - Body ground Always 11 to 14 V

    3. Reinstall the IG2 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY)

    OK

  10. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)


    1. Remove the IG2 relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2 (IG2 relay terminal) - Body ground Always Below 1 Ω

    3. Reinstall the IG2 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BODY GROUND)

    OK

  11. CHECK HARNESS AND CONNECTOR (IG2 RELAY - POWER MANAGEMENT CONTROL ECU)


    1. Disconnect the power management control ECU connector.

    2. Remove the IG2 relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      1 (IG2 relay terminal) - A81-2 (IG2D) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1 (IG2 relay terminal) or A81-2 (IG2D) - Body ground Always 10 kΩ or higher

    4. Reconnect the power management control ECU connector.

    5. Reinstall the IG2 relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - POWER MANAGEMENT CONTROL ECU)

    OK

    GO TO ENTRY AND START SYSTEM Click here