SFI SYSTEM 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 No. 1 integration relay (EFI MAIN relay), closing the contact and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM

A01HQURE05

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
      Tester Connection Condition Specified Condition
      E26-49 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK TERMINAL VOLTAGE (IGSW VOLTAGE)


    1. A01HQF1E12
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A25-32 (IGSW) - Body ground Engine switch on (IG) 11 to 14 V

    NG

    INSPECT NO. 1 INTEGRATION RELAY (IG2 RELAY) Click here

    OK

  3. INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN RELAY)


    1. Inspect the No. 1 integration relay (EFI MAIN relay) Click here.


    NG

    REPLACE NO. 1 INTEGRATION RELAY (EFI MAIN RELAY) Click here

    OK

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


    1. Remove the No. 1 integration relay from the engine room relay block and 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
      1C-9 - A25-2 (+B) Always Below 1 Ω
      1C-10 - A25-3 (+B2) Always Below 1 Ω
      1C-7 - A25-46 (MREL) Always Below 1 Ω
      1C-9 or A25-2 (+B) - Body ground Always 10 kΩ or higher
      1C-10 or A25-3 (+B2) - Body ground Always 10 kΩ or higher
      1C-7 or A25-46 (MREL) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A01HOJ5E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Integration Relay)

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

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

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

    NG

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

    OK

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

  6. INSPECT NO. 1 INTEGRATION RELAY (IG2 RELAY)


    1. Inspect the No. 1 integration relay (IG2 relay) Click here.


    NG

    REPLACE NO. 1 INTEGRATION RELAY (IG2 RELAY) Click here

    OK

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


    1. Remove the No. 1 integration relay from the engine room relay block and 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
      1C-1 - A25-32 (IGSW) Always Below 1 Ω
      1C-1 or A25-32 (IGSW) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A01HNMEE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Integration Relay)

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1D-3 - Body ground Always 11 to 14 V

    NG

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

    OK

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


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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1E-2 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


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

    2. Remove the No. 1 integration 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
      A43-9 (IG2D) - 1C-8 Always Below 1 Ω
      A43-9 (IG2D) or 1C-8 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    GO TO SMART KEY SYSTEM Click here