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

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DTC Code DTC Name
  ECM Power Source Circuit
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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.

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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

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

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PROCEDURE


  1. Click here

    CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. A01NLUDE08

      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
      Table 1. Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

    3. Reconnect the ECM connector.


  2. Click here

    INSPECT ECM (IGSW VOLTAGE)


    1. A01NM3YE09

      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
      Table 2. Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

    4. Reconnect the ECM connector.


  3. Click here

    INSPECT RELAY (EFI MAIN RELAY)


    1. A01NJ36E03

      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.


  4. Click here

    CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM)


    1. A01NIOJE02

      Remove the EFI MAIN 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 (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
      Table 3. Text in Illustration
      *1 Engine Room Relay Block *2

      Front view of wire harness connector

      (to ECM)

    4. Reconnect the ECM connector.

    5. Reinstall the EFI MAIN relay.


  5. Click here

    CHECK HARNESS AND CONNECTOR (BATTERY - EFI MAIN RELAY)


    1. A01NLEYE02

      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
      Table 4. Text in Illustration
      *1 Engine Room Relay Block

    5. Reinstall the EFI MAIN relay.

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

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


  6. Click here

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


    1. A01NLEYE02

      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
      Table 5. Text in Illustration
      *1 Engine Room Relay Block

    3. Reinstall the EFI MAIN relay.


  7. Click here

    INSPECT RELAY (IG2 RELAY)


    1. A01NJ36E46

      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.


  8. Click here

    CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM)


    1. A01NLD2E02

      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
      Table 6. Text in Illustration
      *1 Engine Room Relay Block *2

      Front view of wire harness connector

      (to ECM)

    4. Reinstall the IG2 relay.

    5. Reconnect the ECM connector.


  9. Click here

    CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE)


    1. A01NN26E02

      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
      Table 7. Text in Illustration
      *1 Engine Room Relay Block

    3. Reinstall the IG2 relay.


  10. Click here

    CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)


    1. A01NN26E02

      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
      Table 8. Text in Illustration
      *1 Engine Room Relay Block

    3. Reinstall the IG2 relay.


  11. Click here

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


    1. A01NIX3E02

      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
      Table 9. Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Management Control ECU)

      		 *2 Engine Room Relay Block

    4. Reconnect the power management control ECU connector.

    5. Reinstall the IG2 relay.


  12. Click here

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

  13. Click here

    REPLACE RELAY (EFI MAIN RELAY)

  14. Click here

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

  15. Click here

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

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

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    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLEClick here

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    REPLACE RELAY (IG2 RELAY)

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

  20. Click here

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

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

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

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    GO TO ENTRY AND START SYSTEMClick here