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SFI SYSTEM(w/o Canister Pump Module) ECM Power Source Circuit

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DTC Code DTC Name
  ECM Power Source Circuit
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DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to IGSW of the ECM. When the transistor in the MREL circuit operates, current flows from the battery to ground through the drive circuit of the EFI-MAIN NO. 1 relay, thus operating the relay which supplies power to the +B and +B2 terminals of the ECM.

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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

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

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PROCEDURE


  1. Click here

    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
      A24-10 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  2. *a Front view of wire harness connector (to ECM)
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    CHECK TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE)


    1. Disconnect the ECM connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A24-2 (IGSW) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

  3. Click here

    INSPECT EFI-MAIN NO. 1 RELAY


    1. Inspect the EFI-MAIN NO. 1 relay.

      Click here

      Result
      Proceed to
      OK
      NG

  4. Click here

    CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - ECM)


    1. Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

      Tip:

      Remove the VVT, EFI-MAIN NO. 2 and EFI-MAIN NO. 3 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

    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
      2 (EFI-MAIN NO. 1 relay) - A24-15 (MREL) Always Below 1 Ω
      5 (EFI-MAIN NO. 1 relay) - A24-9 (+B) Always Below 1 Ω
      5 (EFI-MAIN NO. 1 relay) - A24-35 (+B2) Always Below 1 Ω
      2 (EFI-MAIN NO. 1 relay) or A24-15 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      5 (EFI-MAIN NO. 1 relay), A24-9 (+B) or A24-35 (+B2) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly *2 EFI-MAIN NO. 1 Relay
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    CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 1 RELAY)


    1. Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 (EFI-MAIN NO. 1 relay) - Body ground Always 11 to 14 V
      1 (EFI-MAIN NO. 1 relay) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    • OK

      PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLEClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 1 RELAY)

  6. Click here

    INSPECT IG2 NO. 1 RELAY


    1. Inspect the IG2 NO. 1 relay.

      Click here

      Result
      Proceed to
      OK
      NG

  7. Click here

    CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - ECM)


    1. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 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
      3 (IG2 NO. 1 relay) - A24-2 (IGSW) Always Below 1 Ω
      3 (IG2 NO. 1 relay) or A24-2 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly *2 IG2 NO. 1 Relay
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    CHECK TERMINAL VOLTAGE (POWER SOURCE OF IG2 NO. 1 RELAY)


    1. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      5 (IG2 NO. 1 relay) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IG2 NO. 1 RELAY)

  9. Click here

    CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - BODY GROUND)


    1. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (IG2 NO. 1 relay) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (w/ Smart Entry and Start System) A
      OK (w/o Smart Entry and Start System) B
      NG C

  10. Click here

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - IG2 NO. 1 RELAY)


    1. Disconnect the certification ECU (smart key ECU assembly) connector.

    2. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E39-17 (IG1D) - 1 (IG2 NO. 1 relay) Always Below 1 Ω
      E39-17 (IG1D) or 1 (IG2 NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

      GO TO SMART ENTRY AND START SYSTEMClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  11. Click here

    INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

  12. Click here

    CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 NO. 1 RELAY)


    1. Disconnect the ignition switch assembly connector.

    2. Remove the IG2 NO. 1 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
      K30-8 (IG1) - 1 (IG2 NO. 1 relay) Always Below 1 Ω
      K30-8 (IG1) or 1 (IG2 NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

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

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR