SFI SYSTEM(for Rear Air Fuel Ratio Sensor) ECM Power Source Circuit

DESCRIPTION

When the engine switch is turned on (IG), 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 semiconductor power integration ECU (EFI-MAIN relay), closing the contact of the EFI-MAIN relay and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM

B007ZEAE05

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK SEMICONDUCTOR POWER INTEGRATION ECU (POWER SOURCE)

    B007ZZDC02
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

    1. Disconnect the semiconductor power 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 POWER INTEGRATION ECU)

    OK

  2. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - BODY GROUND)


    1. Disconnect the semiconductor power 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

  3. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (EFI-MAIN RELAY, IG2 RELAY)


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

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - ECM)


    1. Disconnect the semiconductor power 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 - A46-6 (IGSW) Always Below 1 Ω
      1G-6 - A46-46 (MREL) Always Below 1 Ω
      1G-8 - A46-2 (+B) Always Below 1 Ω
      1G-7 - A46-3 (+B2) Always Below 1 Ω
      1G-4 or A46-6 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      1G-6 or A46-46 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      1G-8 or A46-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      1G-7 or A46-3 (+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

  5. 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
      D1-53 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - SEMICONDUCTOR POWER INTEGRATION ECU)


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

    2. Disconnect the semiconductor power integration ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J41-17 (IG1D) - 1E-1 Always Below 1 Ω
      J41-17 (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 ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR