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 NO.1 relay, closing the contact of the EFI-MAIN NO.1 relay and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM

B003NDZE03

CAUTION / NOTICE / HINT

Note


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

  • After turning ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

PROCEDURE


  1. CHECK TERMINAL VOLTAGE (IGSW VOLTAGE)

    B003KI3C04
    *a Rear 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 Condition Specified Condition
      G144-21 (IGSW) - 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 (IGNITION SWITCH ASSEMBLY - ECM) Click here

    C

    CHECK HARNESS AND CONNECTOR (NO. 4 INSTRUMENT PANEL RELAY BLOCK - ECM) Click here

    A

  2. 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
      C83-12 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK TERMINAL VOLTAGE (POWER SOURCE OF INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. B003Q13C08
      *a

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)

      Disconnect the instrument panel junction block assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2B-1 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    OK

  4. INSPECT EFI-MAIN NO. 1 RELAY


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

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    OK

  5. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - ECM, BODY GROUND)


    1. Disconnect the instrument panel junction block assembly 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
      2G-5 - G144-23 (+B) Always Below 1 Ω
      2G-5 - G144-22 (+B2) Always Below 1 Ω
      2P-9 - G145-36 (MREL) Always Below 1 Ω
      2J-5 - Body ground Always Below 1 Ω
      2G-5 or G144-23 (+B) - Body ground and other terminals Always 10 kΩ or higher
      2G-5 or G144-22 (+B2) - Body ground and other terminals Always 10 kΩ or higher
      2P-9 or G145-36 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      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

  6. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - ECM)


    1. Disconnect the ignition switch 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
      G135-3 (IG2) - G144-21 (IGSW) Always Below 1 Ω
      G135-3 (IG2) or G144-21 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

  8. CHECK HARNESS AND CONNECTOR (NO. 4 INSTRUMENT PANEL RELAY BLOCK - ECM)


    1. Disconnect the ECM connector.

    2. Remove the IG2 relay from No. 4 instrument panel relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G144-21 (IGSW) - IG2 Relay terminal 3 Always Below 1 Ω
      G144-21 (IGSW) or IG2 Relay terminal 3 - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (BATTERY - NO. 4 INSTRUMENT PANEL RELAY BLOCK)


    1. Disconnect the cable from the positive (+) battery terminal.

    2. Remove the IG2 relay from No. 4 instrument panel relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Battery cable positive (+) terminal - IG2 Relay terminal 5 Always Below 1 Ω
      Battery cable positive (+) terminal or IG2 Relay terminal 5 - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    GO TO SMART ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR