SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to the IGSW terminal of the ECM.

The output signal from the MREL terminal of the ECM causes a current to flow to the coil of the semiconductor pwr integration ECU (EFI MAIN relay), closing the contacts and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM

A0027MRE01
A002ALCE01

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU VOLTAGE)


    1. Disconnect the semiconductor pwr integration ECU 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
      1E-1 - Body ground Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (w/o Smart Entry and Start System) B
      NG (w/ Smart Entry and Start System) C

    B

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

    C

    CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - SEMICONDUCTOR PWR INTEGRATION ECU) Click here

    A

  2. CHECK SEMICONDUCTOR PWR INTEGRATION ECU (POWER SOURCE)

    A002BUIC01
    *1 No. 1 Engine Room Relay Bock and No. 1 Junction Block Assembly

    1. Disconnect the semiconductor pwr integration ECU connector.

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

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - SEMICONDUCTOR PWR INTEGRATION ECU)

    OK

  3. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BODY GROUND)


    1. Disconnect the semiconductor pwr integration ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1D-14 - Body ground Always Below 1 Ω
      1G-5 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT SEMICONDUCTOR PWR INTEGRATION ECU (EFI MAIN RELAY, IG2 RELAY)


    1. Inspect the semiconductor pwr integration ECU (EFI MAIN relay, IG2 relay).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SEMICONDUCTOR PWR INTEGRATION ECU Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - ECM)


    1. Disconnect the semiconductor pwr integration ECU connector.

    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
      1G-4 - A43-4 (IGSW) Always Below 1 Ω
      1G-6 - A43-46 (MREL) Always Below 1 Ω
      1G-1 - A43-2 (+B) Always Below 1 Ω
      1G-2 - A43-3 (+B2) Always Below 1 Ω
      1G-4 or A43-4 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      1G-6 or A43-46 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      1G-1 or A43-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      1G-2 or A43-3 (+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

  6. 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
      C1-53 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. CHECK HARNESS AND CONNECTOR (BATTERY - IGNITION SWITCH ASSEMBLY)


    1. Disconnect the ignition switch assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      F50-4 (AM2) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - IGNITION SWITCH ASSEMBLY)

    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

  9. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - SEMICONDUCTOR PWR INTEGRATION ECU)


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

    2. Disconnect the semiconductor pwr integration ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F10-3 (IG1D) - 1E-1 Always Below 1 Ω
      F10-3 (IG1D) or 1E-1 - 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 SMART ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR