SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, battery voltage is applied to the IGSW terminal of the ECM. The output signal from the MREL terminal of the ECM causes current to flow to the coil of the EFI-MAIN relay, closing the contact of the EFI-MAIN relay and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM

B008KM4E03

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF NO. 1 INTEGRATION RELAY)


    1. Disconnect the 1A and 1B No. 1 integration relay connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1A-10 - Body ground Always 11 to 14 V
      1B-3 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. INSPECT NO. 1 INTEGRATION RELAY (EFI-MAIN RELAY, IG2 NO. 1 RELAY)


    1. Inspect the No. 1 integration relay (EFI-MAIN relay, IG2 NO. 1 relay).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 1 INTEGRATION RELAY Click here

    OK

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


    1. Disconnect the 1A and 1B No. 1 integration relay connector.

    2. Disconnect the A38 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1A-9 - A38-6 (IGSW) Always Below 1 Ω
      1B-6 - A38-46 (MREL) Always Below 1 Ω
      1B-4 - A38-2 (+B) Always Below 1 Ω
      1B-4 - A38-3 (+B2) Always Below 1 Ω
      1A-9 or A38-6 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      1B-6 or A38-46 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      1B-4 or A38-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      1B-4 or A38-3 (+B2) - Body ground and other terminals Always 10 kΩ or higher

      Tech Tips

      If a short is detected in any of the above circuits, there may be a malfunction in the circuit of a connected ECU.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the 1A and 1B No. 1 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1A-8 - Body ground Always Below 1 Ω
      1B-5 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 INTEGRATION RELAY - BODY GROUND)

    OK

  5. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. Disconnect the C62 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C62-53 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  6. INSPECT TERMINAL VOLTAGE (IGSW VOLTAGE)

    B008LGFC81
    *a

    Front view of wire harness connector

    (to ECM)

    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 Switch Condition Specified Condition
      A38-6 (IGSW) - Body ground Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (w/ Entry and Start System) B
      NG (w/o Entry and Start System) C

    A

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

    C

    CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH - NO. 1 INTEGRATION RELAY) Click here

    B

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


    1. Disconnect the F1 certification ECU (smart key ECU assembly) connector.

    2. Disconnect the 1A No. 1 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F1-17 (IG1D) - 1A-7 Always Below 1 Ω
      F1-17 (IG1D) or 1A-7 - Body ground and other terminals Always 10 kΩ or higher

      Tech Tips

      If a short is detected in any of the above circuits, there may be a malfunction in the circuit of a connected ECU.

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 1 INTEGRATION RELAY)

  8. CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH - NO. 1 INTEGRATION RELAY)


    1. Disconnect the F12 ignition or starter switch assembly connector.

    2. Disconnect the 1A No. 1 integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F12-8 (IG1) - 1A-7 Always Below 1 Ω
      F12-8 (IG1) or 1A-7 - Body ground and other terminals Always 10 kΩ or higher

      Tech Tips

      If a short is detected in any of the above circuits, there may be a malfunction in the circuit of a connected ECU.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION OR STARTER SWITCH - NO. 1 INTEGRATION RELAY)

    OK

  9. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY


    1. Inspect the ignition or starter switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY Click here