SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to on (IG), battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes current to flow to the coil, closing the contacts of the engine room junction block assembly (EFI relay) and supplying power to terminal +B and +B2 of the ECM.

WIRING DIAGRAM

A017F9TE12
A017DUDE01

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 (Check for Open)
      Tester Connection Condition Specified Condition
      B48-12 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.


    NG

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

    OK

  2. CHECK ECM (IGSW VOLTAGE)


    1. A017G3PE21
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D55-21 (IGSW) - Body ground Ignition switch on (IG) 11 to 14 V

    3. Reconnect the ECM connector.


    NG

    INSPECT IG2 RELAY Click here

    OK

  3. CHECK ECM (+B AND +B2 TERMINAL VOLTAGE)


    1. A017G3PE27
      Text in Illustration
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D56-22 (+B) - B48-12 (E1) Ignition switch on (IG) 11 to 14 V
      D56-23 (+B2) - B48-12 (E1) Ignition switch on (IG) 11 to 14 V

    NG

    INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY) Click here

    OK

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

  4. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY)


    1. Inspect the engine room junction block assembly Click here.


    NG

    REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY) Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM)


    1. Remove the engine room junction block assembly from the engine room relay block.

    2. Disconnect the engine room junction block assembly connector.

    3. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2E-6 - D56-22 (+B) Always Below 1 Ω
      2E-6 - D56-23 (+B2) Always Below 1 Ω
      2E-9 - D56-9 (MREL) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2E-6 or D56-22 (+B) or D56-23 (+B2) - Body ground Always 10 kΩ or higher
      2E-9 or D56-9 (MREL) - Body ground Always 10 kΩ or higher

    5. Reconnect the ECM connector.

    6. Reconnect the engine room junction block assembly connector.

    7. Reinstall the engine room junction block assembly.


    NG

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

    OK

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


    1. Remove the engine room junction block assembly from the engine room relay block.

    2. Disconnect the engine room junction block assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2E-10 - Body ground Always Below 1 Ω

    4. Reconnect the engine room junction block assembly connector.

    5. Reinstall the engine room junction block assembly.


    NG

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

    OK

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

  7. INSPECT IG2 RELAY


    1. A017BXOE01

      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 IG2 RELAY

    OK

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


    1. Disconnect the ECM 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
      IG2 relay terminal 3 - D55-21 (IGSW) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      IG2 relay terminal 3 or D55-21 (IGSW) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the IG2 relay.


    NG

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

    OK

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


    1. A017ECOE04
      Text in Illustration
      *1 Engine Room Relay Block

      Remove the IG2 relay from the engine room relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      5 - 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
      IG2 relay terminal 2 - Body ground Always Below 1 Ω

    3. Reinstall the IG2 relay.

      Result
      Result Proceed to
      OK (w/ smart entry and start system) A
      OK (w/o smart entry and start system) B
      NG C

    B

    CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 RELAY) Click here

    C

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

    A

  11. CHECK HARNESS AND CONNECTOR (IG2 RELAY - MAIN BODY ECU)


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

    2. Disconnect the main body ECU connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      IG2 relay terminal 1 - D6-11 (IG2D) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      IG2 relay terminal 1 or D6-11 (IG2D) - Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reconnect the main body ECU connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - MAIN BODY ECU)

    OK

    CHECK SMART ENTRY AND START SYSTEM Click here

  12. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 RELAY)


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

    2. Disconnect the ignition switch assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      D21-6 (IG2) - IG2 relay terminal 1 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D21-6 (IG2) or IG2 relay terminal 1 - Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reconnect the ignition switch assembly connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 RELAY)

    OK

  13. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly Click here.


    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - BATTERY)